Weight Converter - Kilograms, Pounds, Stone, Ounces, Tonnes, Carats and Pawns
Convert any weight between the metric units (mg, g, kg, tonne), the pound family (ounce, pound, stone, US ton, UK ton) and the gem and gold units (carat, troy ounce and the Sri Lankan pawn).
Maintained by Hirantha Sandaruwan Lakshan. Updated 13 October 2026.
About this tool
Every factor is exact: 1 pound is 0.45359237 kg and 1 stone is 6.35029318 kg. A stone and pounds helper turns a body weight such as 11 st 4 lb into kilograms (71.66759446 kg) and back.
How it works
Every weight is held as an exact fraction of a kilogram, so long chains such as stone to pounds to ounces to grams never pick up rounding errors. A conversion multiplies by the unit you have and divides by the unit you want, using whole numbers rather than floating point, and a conversion followed by its reverse returns the number you typed. The answer is rounded only when it is shown: Auto shows an exact result in full when it fits in 14 digits and otherwise rounds to 10 significant digits.
The pound is exactly 0.45359237 kg, fixed by the 1959 international yard and pound agreement. Everything else follows from it. An ounce is 1/16 of a pound (28.349523125 g), a stone is 14 pounds (6.35029318 kg), a US or short ton is 2,000 pounds (907.18474 kg) and a UK or long ton is 2,240 pounds (1,016.0469088 kg). NIST Handbook 44 and the UK Weights and Measures Act 1985 give the same relations. The tonne, or metric ton, is 1,000 kg.
Three units need care. The two tons differ by 12 percent (2,240 divided by 2,000 is 1.12), and a tonne is neither of them. The carat is a mass, exactly 200 mg, used for gemstones, and it is not the karat (22K, 24K) that measures the purity of gold. The troy ounce (480 grains, exactly 31.1034768 g) is used for precious metals and is about 9.7 percent heavier than the ordinary ounce.
In Sri Lanka gold jewellery is priced by the sovereign, which people commonly call a pawn. SDB Bank's gold pawning page refers to a Sovereign (8g) and quotes its advances per 8 g, and the Regional Development Bank's pawning page also quotes its advances for 8 g, both checked on 2026-10-13, so this converter uses 1 pawn = 8 g. Neither page defines the word pawn, and it is a trade and banking convention, not an SI or legal unit, so confirm the weight with your jeweller or lender. The old Sinhala weights pala and kalan are not included, because we could not confirm a gram value for them from a reliable source.
Worked examples
Body weight: 11 st 4 lb in kilograms
11 st 4 lb is 11 x 14 + 4 = 158 pounds. 158 x 0.45359237 = 71.66759446 kg. Going back, 70 kg is 154.3235835 pounds, which the helper shows as 11 st 0.3 lb.
Kilograms to pounds
1 kg is 1 divided by 0.45359237 = 2.204622622 pounds, rounded to 10 significant digits. So 10 kg is 22.04622622 pounds.
Gold in pawns and troy ounces
A 2 pawn chain weighs 2 x 8 = 16 g. A troy ounce is 31.1034768 g, so 16 g is 0.5144119451 troy ounces. The 8 g pawn is a Sri Lankan trade convention.
US tons and UK tons
5 US tons is 5 x 907.18474 = 4,535.9237 kg. 5 UK tons is 5 x 1,016.0469088 = 5,080.234544 kg. Always check which ton a document means.
Weight units in kilograms (exact values)
| Unit | Defined as | Kilograms |
|---|---|---|
| milligram | 1/1,000,000 kg | 0.000001 |
| gram | 1/1,000 kg | 0.001 |
| kilogram | SI base unit | 1 |
| tonne (metric ton) | 1,000 kg | 1,000 |
| ounce | 1/16 pound | 0.028349523125 |
| pound | 1959 agreement, exact | 0.45359237 |
| stone | 14 pounds | 6.35029318 |
| US ton (short ton) | 2,000 pounds | 907.18474 |
| UK ton (long ton) | 2,240 pounds | 1,016.0469088 |
| carat (metric) | 200 mg | 0.0002 |
| troy ounce | 480 grains | 0.0311034768 |
| pawn | 8 g, trade convention | 0.008 |
Frequently asked questions
How many pounds are in a kilogram?
2.204622622 to 10 significant digits. The pound is defined as exactly 0.45359237 kg, so you divide kilograms by 0.45359237 to get pounds, or multiply pounds by 0.45359237 to get kilograms.
How do I convert stone to kg?
Multiply the stone by 6.35029318, which is 14 pounds x 0.45359237. For example 12 stone is 76.20351816 kg. For stone and pounds together, change it all to pounds first (stone x 14 + pounds), then multiply by 0.45359237, or use the helper under the converter.
What is the difference between a US ton and a UK ton?
A US (short) ton is 2,000 pounds, which is 907.18474 kg. A UK (long) ton is 2,240 pounds, which is 1,016.0469088 kg. The metric tonne is 1,000 kg. They are different units that are all called a ton, so check which one a price or shipping document uses.
Is a carat the same as a karat?
No. A carat is a unit of mass for gemstones, exactly 200 mg, so 5 carats is 1 g. A karat (22K, 24K) measures how pure gold is, as parts out of 24. A 22 karat chain is 22 parts gold in 24, and its weight is a separate matter, measured in grams or pawns.
How many grams is a pawn of gold in Sri Lanka?
This converter uses 8 g, the figure SDB Bank prints for a sovereign on its gold pawning page, and the Regional Development Bank quotes its gold advances for 8 g in the same way (both checked 2026-10-13). In everyday speech a sovereign is commonly called a pawn, although the bank pages do not use that word. It is a trade convention, not a legal unit, so ask your jeweller to confirm the weight of a particular piece.
Why is a troy ounce different from an ounce?
They are two different ounces. The everyday (avoirdupois) ounce is 28.349523125 g, and the troy ounce used for gold and silver is 31.1034768 g, about 9.7 percent heavier. A troy ounce has 480 grains and an ordinary ounce has 437.5 grains.
Does the converter include the old pala and kalan?
No. They are historical weights, and we could not confirm a modern gram value for either one from a reliable source. We leave them out instead of guessing.
Is weight the same as mass?
Strictly, mass is the amount of matter and weight is the force of gravity on it. Everyday scales and all the units on this page measure mass, so this tool converts mass. For daily use you can treat the two as the same.
Sources & references
- NIST Handbook 44 (2026 edition), Appendix C, General Tables of Units of Measurement (exact inch, foot, yard, mile, rod, chain, furlong, square perch, acre, cup, tablespoon, teaspoon, US gallon, pound, carat, troy ounce, nautical mile), checked 2026-10-13
- NIST Special Publication 811 (2008), Appendix B.8, factors for units listed alphabetically (exact foot, inch, yard, mile, nautical mile, carat, grain, hectare, imperial gallon and the temperature formulas), checked 2026-10-13
- Weights and Measures Act 1985, Schedule 1 (yard, mile, acre, rood, stone, pound, imperial gallon and fluid ounce definitions, as revised and current on 5 October 2026; the page flags that Schedule 1 is due to be omitted by the Product Regulation and Metrology Act 2025 from a day to be appointed, so the page may change), legislation.gov.uk, checked 2026-10-13
- SDB bank, Gold Pawning Rates in Sri Lanka (refers to a Sovereign (8g) and quotes advances per 8 g), checked 2026-10-13
- Regional Development Bank, gold pawning advances (the table quotes advances for 8g at each karat), checked 2026-10-13
Updated Oct 13, 2026