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Weight Converter — kg, lbs, oz, g, Stone & 13 Units Total

Convert weight between 13 units instantly — metric, imperial & troy. Conversion tables, formulas & references. Free, runs in your browser.

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Result
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All conversion factors verified against NIST Handbook 44 and tested for roundtrip accuracy across all 13 supported units. — Go Tools Engineering Team · Mar 18, 2026

Our team verifies all conversion factors against NIST standards and tests every unit pair for roundtrip accuracy.

Weight Quick Reference — Key Numbers to Know

How Many Pounds in a Kilogram?

1 kg = 2.205 lbs This is based on the NIST definition where 1 lb = 453.59237 g exactly. For quick mental math, multiply kg by 2.2.

How Many Grams in an Ounce?

1 oz = 28.350 grams One avoirdupois ounce (the everyday ounce) equals 28.3495 grams. A troy ounce (precious metals) equals 31.1035 grams.

How Many Ounces in a Pound?

1 pound = 16 ounces One avoirdupois pound contains exactly 16 ounces. This is an exact definition in the US customary and British imperial systems.

How Many Pounds in a Stone?

1 stone = 14 pounds One stone equals exactly 14 pounds (6.35 kg). The stone is commonly used for body weight in the UK and Ireland.

How Many Grams in a Kilogram?

1 kg = 1,000 grams This is an exact definition in the metric system. Also: 1 kg = 1,000,000 mg = 1,000,000,000 mcg.

How Many Milligrams in a Gram?

1 g = 1,000 mg This is an exact metric definition. Also: 1 g = 1,000,000 mcg. Move the decimal 3 places to convert.

How Many Grams in a Pound?

1 lb = 453.592 grams Based on the NIST exact definition: 1 lb = 453.59237 g. For quick math, use 454 g per pound.

How Many Kilograms in a Stone?

1 stone = 6.350 kg One stone = 14 pounds = 6.35029 kg. Used for body weight in the UK and Ireland.

Weight Conversion Formulas with Worked Examples

Mathematical formulas for the most common weight conversions, with worked examples.

Kilograms to Pounds

pounds = kilograms × 2.2046226218

pounds ≈ kilograms × 2.2 (quick estimate)

70 kilograms →

  1. 70 × 2.2046226218
  2. = 154.324

= 154.324 pounds

Pounds to Kilograms

kilograms = pounds × 0.45359237

kilograms = pounds ÷ 2.2046

150 pounds →

  1. 150 × 0.45359237
  2. = 68.0389

= 68.0389 kilograms

Ounces to Grams

grams = ounces × 28.349523125

grams ≈ ounces × 28.35 (quick estimate)

8 ounces →

  1. 8 × 28.349523125
  2. = 226.796

= 226.796 grams

Grams to Ounces

ounces = grams ÷ 28.349523125

ounces ≈ grams ÷ 28 (quick estimate)

200 grams →

  1. 200 ÷ 28.349523125
  2. = 7.05479

= 7.05479 ounces

Stone to Kilograms

kilograms = stone × 6.35029318

12 stone →

  1. 12 × 6.35029318
  2. = 76.2035

= 76.2035 kilograms

Troy Ounces to Grams

grams = troy ounces × 31.1034768

5 troy ounces →

  1. 5 × 31.1034768
  2. = 155.517

= 155.517 grams

Milligrams to Grams

grams = milligrams ÷ 1000

move decimal 3 places left

500 milligrams →

  1. 500 ÷ 1000
  2. = 0.5

= 0.5 grams

Carats to Grams

grams = carats × 0.2

grams = carats ÷ 5

3 carats →

  1. 3 × 0.2
  2. = 0.6

= 0.6 grams

What Is a Weight & Mass Unit Converter?

A weight and mass unit converter is a tool that translates measurements between different units of mass — covering metric (micrograms, milligrams, grams, kilograms, metric tons), avoirdupois/imperial (ounces, pounds, stone, short tons, long tons), and specialty units (carats, troy ounces, grains).

The metric system defines mass through the kilogram, the SI base unit. Since the 2019 BIPM redefinition of SI base units, the kilogram has been defined by fixing the numerical value of the Planck constant (h = 6.62607015 × 10⁻³⁴ J·s), replacing the International Prototype of the Kilogram (IPK) — a platinum-iridium cylinder kept in a vault at BIPM near Paris. This redefinition anchors the kilogram to a universal constant of nature. One kilogram = 1,000 grams = 1,000,000 milligrams. The avoirdupois system, used in the US and UK for everyday commerce, defines 1 pound = 16 ounces = 453.59237 grams exactly. The stone (14 pounds) is still used for body weight in the UK.

Specialty units serve specific industries: the carat (0.2 grams) is the universal standard for gemstone weight; the troy ounce (31.1035 g) is the standard for precious metals trading; and the grain (64.79891 mg) is used in ballistics and pharmacy.

Three different 'tons' cause frequent confusion: the metric ton (1,000 kg), the US short ton (2,000 lbs / 907.2 kg), and the British long ton (2,240 lbs / 1,016 kg). This converter handles all three.

Weight measurement conventions vary worldwide. The United States uses pounds and ounces for nearly everything — groceries, body weight, shipping. The United Kingdom uses a hybrid system: stone and pounds for body weight, but kilograms and grams in shops (by law since 2000). Continental Europe, East Asia, and most of the world use kilograms and grams exclusively. China uses the 斤 (jīn, 1 jīn = 500 g) as an informal everyday unit alongside kilograms. In the precious metals and gemstone industries, troy ounces and carats are universal regardless of country.

All conversions use the exact factors defined by NIST and are calculated entirely in your browser — no data is transmitted to any server, keeping your measurements completely private. Need to convert other measurement types? Try our length converter for distance units, volume converter for liquid measurements, or temperature converter for °C, °F and Kelvin.

// Key weight conversion factors:
// 1 kg       = 1000 g
// 1 lb       = 453.59237 g (exact, by definition)
// 1 oz       = 28.349523125 g
// 1 stone    = 6350.29318 g (14 lbs)
// 1 troy oz  = 31.1034768 g
// 1 carat    = 0.2 g (exact)
// 1 grain    = 0.06479891 g

// JavaScript conversion examples:
const kgToLbs = (kg) => kg * 2.2046226218;
const ozToGrams = (oz) => oz * 28.349523125;
const stoneToKg = (st) => st * 6.35029318;

console.log(kgToLbs(70));      // 154.324
console.log(ozToGrams(8));     // 226.796
console.log(stoneToKg(11));    // 69.8532

Key Features of This Weight Converter

13 Weight & Mass Units Supported

Convert between microgram, milligram, gram, kilogram, metric ton, ounce, pound, stone, short ton, long ton, carat, troy ounce, and grain.

Instant Real-Time Conversion

Results update as you type — no need to click a convert button. Change units and see the result immediately.

Grouped Unit Selector

Units are organized into Metric, Imperial, and Specialty groups for quick selection.

Metric, Avoirdupois & Troy Systems

Clearly separates everyday ounces (28.35 g) from troy ounces (31.10 g), and distinguishes metric tons, short tons, and long tons.

Industry-Specific Units

Includes carats for gemstones, troy ounces for precious metals, and grains for pharmacy and ballistics — the units professionals actually need.

100% Browser-Based & Private

All calculations happen locally in your browser. No server requests, no tracking, no data storage — your values never leave your device.

Weight Conversion Examples — kg, lbs, oz, Stone

Kilograms to Pounds — Body Weight

70
154.324 lb

One kilogram equals approximately 2.20462 pounds. A 70 kg person weighs about 154.3 pounds. This is the single most common weight conversion, used daily in fitness, healthcare, and travel between metric and imperial countries.

Ounces to Grams — Cooking & Nutrition

8
226.796 g

One avoirdupois ounce equals approximately 28.3495 grams. Eight ounces (half a pound) is about 226.8 grams. This conversion is essential when following recipes that mix US and metric measurements.

Stone to Kilograms — UK Body Weight

11
69.8532 kg

One stone equals exactly 14 pounds or approximately 6.35029 kilograms. Eleven stone (154 lbs) is about 69.85 kg. The stone is still widely used for body weight in the UK and Ireland.

Carats to Grams — Gemstone Weight

2.5
0.5 g

One carat equals exactly 0.2 grams (200 milligrams). A 2.5 carat diamond weighs exactly 0.5 grams. The carat is the standard unit for gemstones and pearls, defined by international agreement since 1907.

Troy Ounces to Grams — Precious Metals

1
31.1035 g

One troy ounce equals approximately 31.1035 grams — about 10% heavier than a standard avoirdupois ounce (28.35 g). Gold, silver, and platinum are always quoted in troy ounces on commodity markets.

Pounds to Ounces — Shipping & Postage

3.5
56 oz

One pound contains exactly 16 ounces. A 3.5-pound package weighs 56 ounces. Postal services often require weight in ounces for accurate rate calculation, especially for packages near weight thresholds.

How to Convert kg to lbs, oz to g & More

Quick reference for the most popular weight and mass unit conversions between metric, avoirdupois, and specialty systems.

How to Convert Kilograms to Pounds

Kilogram (kg) → Pound (lb)

Multiply the number of kilograms by 2.20462 to get pounds. For example, 70 kg = 154.32 lbs. This is the most common weight conversion, used for body weight, luggage limits, and product labeling.

70 kg → 154.324 lb

For quick mental math, multiply kg by 2 and add 10%. Example: 80 kg → 160 + 16 = 176 lbs (exact: 176.37 lbs).

Try it above — enter your value and see the result instantly.

How to Convert Pounds to Kilograms

Pound (lb) → Kilogram (kg)

Divide the number of pounds by 2.20462, or multiply by 0.45359. For example, 150 lbs = 68.04 kg. Essential for converting US product weights to metric for international use.

150 lb → 68.0389 kg

For a quick estimate, halve the pounds and subtract 10%. Example: 200 lbs → 100 - 10 = 90 kg (exact: 90.72 kg).

Try it above — enter your value and see the result instantly.

How to Convert Ounces to Grams

Ounce (oz) → Gram (g)

Multiply the number of ounces by 28.3495 to get grams. For example, 4 oz = 113.4 g. This conversion is commonly used in cooking, nutrition labels, and postal weight calculations.

4 oz → 113.398 g

For a quick estimate, multiply ounces by 28 — it is only 1.2% off from the exact factor.

Try it above — enter your value and see the result instantly.

How to Convert Grams to Ounces

Gram (g) → Ounce (oz)

Divide the number of grams by 28.3495 to get ounces. For example, 200 g = 7.055 oz. Used when converting metric recipe amounts to US measurements.

200 g → 7.05479 oz

For a quick estimate, divide grams by 28. A 100 g chocolate bar is about 3.5 oz.

Try it above — enter your value and see the result instantly.

How to Convert Stone to Kilograms

Stone (st) → Kilogram (kg)

Multiply the number of stone by 6.35029 to get kilograms. For example, 12 stone = 76.2 kg. This conversion is commonly used when converting UK body weight to metric.

12 st → 76.2035 kg

Each stone is 14 lbs or about 6.35 kg. For quick math, multiply stone by 6 and add half a stone's worth (3 kg) — close enough for body weight estimates.

Try it above — enter your value and see the result instantly.

How to Convert Kilograms to Stone

Kilogram (kg) → Stone (st)

Divide the number of kilograms by 6.35029 to get stone. For example, 80 kg = 12.6 stone. Useful for converting metric body weight to the format used in the UK and Ireland.

80 kg → 12.5978 st

Divide kg by 6.35 for stone. To get stone and pounds: take the whole stone number, then convert the decimal remainder (× 14) to pounds.

Try it above — enter your value and see the result instantly.

How to Convert Milligrams to Grams

Milligram (mg) → Gram (g)

Divide milligrams by 1,000 to get grams. For example, 500 mg = 0.5 g. This is the most common conversion in pharmacy and nutrition — every supplement label and drug dosage uses mg.

500 mg → 0.5 g

Simply move the decimal point 3 places left. 250 mg = 0.250 g, 1500 mg = 1.5 g.

Try it above — enter your value and see the result instantly.

How to Convert Carats to Grams

Carat (ct) → Gram (g)

Multiply carats by 0.2 to get grams (or divide by 5). For example, 3 ct = 0.6 g. The carat is the universal unit for gemstone weight, defined exactly as 200 milligrams since 1907.

3 ct → 0.6 g

Dividing carats by 5 gives the same result — easier mental math for round numbers.

Try it above — enter your value and see the result instantly.

Weight Conversion Charts — kg↔lbs, oz↔g, Stone↔kg

Pre-calculated reference tables for the most common weight conversions. Bookmark this page for quick lookups.

Kilograms to Pounds Chart

Kilograms to pounds conversion table (1-100 kg)
KG LB
1 Bag of sugar 2.20462262185
2 4.4092452437
3 6.61386786555
4 8.8184904874
5 Bowling ball 11.0231131092
6 13.2277357311
7 15.4323583529
8 17.6369809748
9 19.8416035966
10 22.0462262185
11 24.2508488403
12 26.4554714622
13 28.660094084
14 30.8647167059
15 33.0693393277
16 35.2739619496
17 37.4785845714
18 39.6832071933
19 41.8878298151
20 44.092452437
25 55.1155655462
30 66.1386786555
35 77.1617917647
40 88.184904874
45 99.2080179832
50 110.231131092
55 121.254244202
60 132.277357311
65 143.30047042
70 Average adult (154 lbs) 154.323583529
75 165.346696639
80 176.369809748
85 187.392922857
90 198.416035966
95 209.439149076
100 Large adult / heavy luggage 220.462262185

Pounds to Kilograms Chart

Pounds to kilograms conversion table (1-200 lbs)
LB KG
1 Loaf of bread 0.45359237
2 0.90718474
3 1.36077711
4 1.81436948
5 Bag of flour 2.26796185
6 2.72155422
7 3.17514659
8 3.62873896
9 4.08233133
10 4.5359237
11 4.98951607
12 5.44310844
13 5.89670081
14 6.35029318
15 6.80388555
16 7.25747792
17 7.71107029
18 8.16466266
19 8.61825503
20 9.0718474
25 11.33980925
30 13.6077711
35 15.87573295
40 18.1436948
45 20.41165665
50 Airline checked bag limit 22.6796185
55 24.94758035
60 27.2155422
65 29.48350405
70 31.7514659
75 34.01942775
80 36.2873896
85 38.55535145
90 40.8233133
95 43.09127515
100 Average 12-year-old 45.359237
105 47.62719885
110 49.8951607
115 52.16312255
120 54.4310844
125 56.69904625
130 58.9670081
135 61.23496995
140 63.5029318
145 65.77089365
150 Average adult (68 kg) 68.0388555
155 70.30681735
160 72.5747792
165 74.84274105
170 77.1107029
175 79.37866475
180 81.6466266
185 83.91458845
190 86.1825503
195 88.45051215
200 90.718474

Ounces to Grams Chart

Ounces to grams conversion table (1-32 oz)
OZ G
1 Slice of bread 28.349523125
2 56.69904625
3 85.048569375
4 113.3980925
5 141.747615625
6 Baseball 170.09713875
7 198.446661875
8 Half pound (227 g) 226.796185
9 255.145708125
10 283.49523125
11 311.844754375
12 Soda can 340.1942775
13 368.543800625
14 396.89332375
15 425.242846875
16 One pound (454 g) 453.59237
18 510.29141625
20 566.9904625
22 623.68950875
24 680.388555
26 737.08760125
28 793.7866475
30 850.48569375
32 907.18474

Stone to Kilograms Chart

Stone to kilograms conversion table (6-25 stone)
ST KG
6 38.10175908
7 44.45205226
8 Small adult (51 kg / 112 lbs) 50.80234544
9 57.15263862
10 63.5029318
11 Average adult (70 kg / 154 lbs) 69.85322498
12 76.20351816
13 82.55381134
14 89 kg / 196 lbs 88.90410452
15 95.2543977
16 Large adult (102 kg / 224 lbs) 101.60469088
17 107.95498406
18 114.30527724
19 120.65557042
20 127 kg / 280 lbs 127.0058636
21 133.35615678
22 139.70644996
23 146.05674314
24 152.40703632
25 158.7573295

Grams to Ounces Chart

Grams to ounces conversion table (10-500 g)
G OZ
10 0.352739619496
20 0.705479238992
30 1.05821885849
40 1.41095847798
50 Medium egg 1.76369809748
60 2.11643771697
70 2.46917733647
80 2.82191695597
90 3.17465657546
100 Standard chocolate bar 3.52739619496
125 4.4092452437
150 5.29109429244
175 6.17294334118
200 Smartphone 7.05479238992
225 7.93664143866
250 8.8184904874
275 9.70033953613
300 10.5821885849
325 11.4640376336
350 12.3458866824
375 13.2277357311
400 14.1095847798
425 14.9914338286
450 15.8732828773
475 16.7551319261
500 17.6369809748

Milligrams to Grams Chart

Milligrams to grams conversion table (1–1000 mg)
MG G
1 0.001
2 0.002
3 0.003
4 0.004
5 Typical melatonin supplement 0.005
6 0.006
7 0.007
8 0.008
9 0.009
10 0.01
25 0.025
50 0.05
75 0.075
100 0.1
200 Caffeine in a cup of coffee 0.2
300 0.3
400 0.4
500 Vitamin C tablet 0.5
600 0.6
700 0.7
800 0.8
900 0.9
1000 = 1 gram 1

Carats to Grams Chart

Carats to grams conversion table (0.25–50 ct)
CT G
0.25 0.05
0.5 Typical engagement ring solitaire 0.1
0.75 0.15
1 Most popular diamond size (0.2 g) 0.2
1.25 0.25
1.5 0.3
1.75 0.35
2 0.4
2.25 0.45
2.5 0.5
2.75 0.55
3 0.6
3.25 0.65
3.5 0.7
3.75 0.75
4 0.8
4.25 0.85
4.5 0.9
4.75 0.95
5 1
10 2
20 4
30 6
40 8
50 10

How to Convert Weight Units Online

  1. 1

    Enter a Value

    Type or paste a numeric value into the input field. The tool accepts integers, decimals, and scientific notation.

  2. 2

    Select the Source Unit

    Choose the unit you are converting from using the 'From' dropdown. Units are organized by system: Metric, Imperial, and Specialty.

  3. 3

    Select the Target Unit

    Choose the unit you want to convert to using the 'To' dropdown. The result updates instantly as you change either unit.

  4. 4

    Copy or Swap

    Click the copy button to copy the result to your clipboard. Use the swap button to reverse the conversion direction instantly.

Common Weight Conversion Mistakes to Avoid

Confusing Mass and Weight Units

Mass (kg, g) measures the amount of matter. Weight (newtons) measures gravitational force. In everyday use they are interchangeable on Earth, but in scientific contexts the distinction matters.

✗ Wrong 
My weight is 70 kg (in a physics calculation)
✓ Correct 
My mass is 70 kg
My weight is 70 × 9.81 = 686.7 N

Confusing Troy Ounces and Avoirdupois Ounces

Troy ounces (31.10 g) are used for precious metals; standard ounces (28.35 g) are used for everything else. Mixing them up causes a 9.7% error in gold, silver, and platinum transactions.

✗ Wrong 
Gold price: $2,000/oz (using 28.35 g per oz)
✓ Correct 
Gold price: $2,000/troy oz (31.1035 g)
1 troy oz ≠ 1 avoirdupois oz

Confusing Metric Tons, Short Tons, and Long Tons

The three 'tons' differ by up to 12%. Using the wrong one in shipping or trade causes significant financial and logistical errors.

✗ Wrong 
Ship 5 tons of cargo (which ton?)
✓ Correct 
Ship 5 metric tons (5,000 kg)
or 5 short tons (4,536 kg)
or 5 long tons (5,080 kg)

Confusing Weight Ounces and Fluid Ounces

Ounces (oz) measure weight/mass. Fluid ounces (fl oz) measure volume. They are only approximately equal for water — for other substances the difference can be dramatic.

✗ Wrong 
8 oz of honey = 8 fl oz of honey
✓ Correct 
8 fl oz of honey ≈ 11.3 oz by weight
(honey is ~1.4× denser than water)

Confusing Net Weight and Gross Weight

Net weight is the product alone; gross weight includes packaging. In international trade, quoting the wrong one causes pricing and logistics errors. A '500 g' food package might have 530 g gross weight.

✗ Wrong 
Shipped 500 g of product (weighed with box)
✓ Correct 
Net weight: 500 g
Gross weight: 530 g (includes packaging)

Confusing Local Weight Units with Kilograms

Regional units like 斤 (jīn, China, 500 g) and livre (France, historically ~489.5 g) are often confused with kilograms. Mixing 斤 and kg doubles or halves the actual weight; confusing livre and pound introduces ~8% error.

✗ Wrong 
3 local units = 3 kg (wrong assumption)
✓ Correct 
1 jin (CN) = 500 g = 0.5 kg
1 livre (FR, historical) ≈ 489.5 g
1 pound (lb) = 453.6 g

When You Need Weight Conversion — 6 Scenarios

Fitness & Healthcare
Convert body weight between kilograms, pounds, and stone for fitness tracking, medical records, and BMI calculations across different measurement systems.
Shipping & Postage
Convert package weight between grams, kilograms, ounces, and pounds for accurate shipping rate calculations and postal compliance.
Cooking & Baking
Convert ingredient weights between grams, ounces, and pounds when following recipes from different countries or scaling portion sizes.
Jewelry & Gemstones
Convert between carats, grams, and troy ounces for gemstone evaluation, precious metal trading, and jewelry manufacturing.
Pharmacy & Medicine
Convert between micrograms, milligrams, grams, and grains for precise pharmaceutical dosage calculations and prescription formulations.
Science & Engineering
Convert between metric and imperial mass units for laboratory measurements, materials science, and engineering specifications.

Technical Details — NIST Factors & Precision

NIST-Defined Conversion Factors
Uses the exact conversion factors published by the National Institute of Standards and Technology: 1 lb = 453.59237 g (exact by definition), 1 troy oz = 31.1034768 g, 1 carat = 0.2 g (exact).
Double-Precision Arithmetic
Uses IEEE 754 double-precision floating-point numbers, providing at least 15 significant digits of precision for all conversions.
Client-Side Processing
All conversion logic runs in JavaScript within your browser. Zero network calls are made — the tool works fully offline once loaded.

Weight Conversion Best Practices — Avoid Costly Mistakes

Distinguish Troy from Avoirdupois
A troy ounce (31.10 g) is about 10% heavier than a standard ounce (28.35 g). Always verify which system is being used when dealing with precious metals versus everyday goods.
Specify the Type of Ton
A metric ton (1,000 kg), short ton (907.2 kg), and long ton (1,016 kg) differ by up to 12%. Always clarify which ton is meant in shipping, trade, and engineering contexts.
Use Grams for Cooking Precision
Volume measurements for ingredients can vary by 20-30% depending on packing. For precise baking and cooking, weigh ingredients in grams using a kitchen scale.
Know Your Audience's Unit System
When communicating weight internationally, always specify the unit explicitly. '150' could mean 150 lbs (68 kg, US), 150 kg (330 lbs, error), or 150 斤 (75 kg, China). In professional contexts, use SI units (kg/g) as the universal standard and provide local equivalents in parentheses.

Weight Conversion FAQ — 15 Common Questions

How many pounds are in a kilogram?
One kilogram equals approximately 2.20462 pounds. For quick mental math, multiply kilograms by 2.2 — this gives a result accurate to within 0.2%. For example, 80 kg × 2.2 = 176 lbs (exact: 176.37 lbs). The precise NIST conversion factor is 1 kg = 2.2046226218 lbs. To convert pounds back to kilograms, divide by 2.2046 or multiply by 0.4536.
How many grams are in an ounce?
One avoirdupois ounce equals approximately 28.3495 grams. For a quick estimate, use 28.35 grams per ounce. Common reference points: 1 oz = 28.35 g, 4 oz (quarter pound) = 113.4 g, 8 oz (half pound) = 226.8 g, 16 oz (one pound) = 453.6 g. Note that a troy ounce (used for precious metals) is heavier at 31.1035 grams.
How many pounds are in a stone?
One stone equals exactly 14 pounds (6.35029 kg). The stone is commonly used in the UK and Ireland for expressing body weight. Common stone-to-pound conversions: 8 stone = 112 lbs, 10 stone = 140 lbs, 12 stone = 168 lbs, 14 stone = 196 lbs, 16 stone = 224 lbs. To convert stone to kilograms, multiply by 6.35029.
What is the difference between a metric ton, a short ton, and a long ton?
A metric ton (tonne) = 1,000 kg = 2,204.6 lbs. A US short ton = 2,000 lbs = 907.2 kg. A British long ton = 2,240 lbs = 1,016 kg. The metric ton is used internationally, the short ton is standard in the US, and the long ton is used in British shipping. The differences are significant: a metric ton is about 10% heavier than a short ton, and a long ton is about 1.6% heavier than a metric ton.
What is the difference between mass and weight?
Mass is the amount of matter in an object, measured in kilograms. Weight is the force of gravity on that mass, measured in newtons. On Earth's surface, a 1 kg mass has a weight of approximately 9.81 newtons. In everyday use, 'weight' and 'mass' are used interchangeably because we almost always measure on Earth. This converter handles mass units — the values are correct anywhere on Earth's surface, though technically your 'weight' varies slightly with altitude and latitude.
What is the difference between a troy ounce and a regular (avoirdupois) ounce?
A troy ounce equals 31.1035 grams, while a standard avoirdupois ounce equals 28.3495 grams — the troy ounce is about 9.7% heavier. Troy ounces are exclusively used for precious metals (gold, silver, platinum, palladium). When a news report says 'gold is $2,000 per ounce,' it always means troy ounces. Confusing the two would cause a 9.7% pricing error.
How can I quickly convert kg to lbs in my head?
The easiest mental math method: multiply by 2 and add 10%. For example, 75 kg: 75 × 2 = 150, plus 10% (15) = 165 lbs (exact: 165.35 lbs). This gives accuracy within 0.2%. Another approach: multiply by 11 and divide by 5, which gives the exact factor of 2.2. For going from lbs to kg, divide by 2.2 — or halve the number and subtract 10%.
How accurate is this weight converter?
This converter uses the exact conversion factors defined by NIST (National Institute of Standards and Technology). All calculations use IEEE 754 double-precision floating-point arithmetic, providing at least 15 significant digits of precision. For everyday conversions, scientific calculations, and commercial transactions, the results are far more precise than any physical scale. The tool runs entirely in your browser with no rounding shortcuts.
Is my data safe when using this weight converter?
Yes, completely. All conversions are performed locally in your browser using JavaScript. No data is sent to any server — there are no network requests, no cookies, and no analytics on your input. The conversion logic runs entirely on your device, meaning your values never leave your browser. You can verify this by disconnecting from the internet and using the tool — it works fully offline once the page has loaded.
How many ounces are in a pound?
One pound contains exactly 16 avoirdupois ounces. This is an exact definition, not an approximation. Useful fractional references: 1/4 lb = 4 oz, 1/2 lb = 8 oz, 3/4 lb = 12 oz. Note that a troy pound (rarely used) contains only 12 troy ounces. When someone says 'pound' and 'ounce' without qualification, they mean the avoirdupois system used in everyday commerce.
How many milligrams are in a gram?
1 g = 1,000 mg exactly. This is a standard metric decimal relationship. Common references: one aspirin tablet = 325 mg, one vitamin C tablet = 500 mg, one caffeine capsule = 200 mg. The mg→g conversion is most frequently used in pharmaceutical dosages, nutrition labels, and laboratory measurements.
How many grams are in a pound?
1 lb = 453.59237 g (exact NIST definition). For quick estimates, use 454 g. Common references: 1/4 lb = 113.4 g (quarter-pounder burger patty), 1/2 lb = 226.8 g, 1 lb butter = 454 g (4 sticks). This conversion comes up frequently when adapting recipes between US and metric measurements. See also our volume converter for liquid ingredient conversions.
What is a grain and where is it used?
1 grain = 64.79891 mg = 0.0648 g. The grain is one of the oldest weight units still in active use, surviving in two specialized fields: pharmacy (aspirin was historically dosed in grains — 5 gr = 325 mg) and ballistics (bullet weights are measured in grains, e.g. a 9mm round = 115–147 gr). Try converting grains using the Specialty unit group above.
How do I convert between 斤 (jīn) and kilograms?
1 斤 (jīn, also called "catty") = 500 g = 0.5 kg. This is the most common everyday weight unit in mainland China, used for groceries, produce, and casual body weight references. 1 kg = 2 斤. Note: Southeast Asian catties differ (Malaysia: 1 catty = 604.79 g). This tool uses international standard units; for 斤 conversions, simply multiply the kg result by 2.
What do common everyday objects weigh?
Weight reference points for building intuition: a paper clip ≈ 1 g, a US quarter coin ≈ 5.67 g, a medium egg ≈ 50 g, a smartphone ≈ 172 g, a liter of water = 1,000 g (1 kg), a bowling ball ≈ 6 kg (13 lbs), an average adult ≈ 70 kg (154 lbs). These anchors help you estimate whether a conversion result is reasonable. For size comparisons, our length converter covers 16 units of distance.

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