Weight Converter
This weight converter changes a value between twelve units: milligrams, grams, kilograms, metric tons, ounces, pounds, stone, US (short) tons, long tons, metric carats, troy ounces and grains. Enter a number, pick the unit you have and the unit you want. The table under the result shows the same weight in every unit, so you can read a recipe, a luggage limit or a gold price in one step.
Updated
Results
- Unit
- Conversion factorOne unit of the source expressed in the target unit
| Unit | Value |
|---|
Results are estimates. See the methodology below.
How to use the converter
- Enter the value. Decimals are fine, for example 2.5 or 0.75.
- From: the unit you are starting with, such as lb.
- To: the unit you need, such as kg.
You get the converted value and the conversion factor for one unit (for example 1 lb = 0.45359237 kg), which is handy if you want to repeat the calculation on paper or in a spreadsheet. The table lists your value in all twelve units at once.
Conversion factors
Every conversion goes through the kilogram, the SI unit of mass: the value is multiplied by the size of the source unit in kilograms and divided by the size of the target unit. Since a notice in the Federal Register of July 1, 1959, the US has defined the pound exactly in terms of the kilogram, so all of these factors are exact.
| Unit | Definition | Exact value |
|---|---|---|
| lb (avoirdupois pound) | international pound | 0.45359237 kg |
| oz | 1/16 lb | 28.349523125 g |
| st (stone) | 14 lb | 6.35029318 kg |
| US ton (short ton) | 2,000 lb | 907.18474 kg |
| long ton | 2,240 lb | 1,016.0469088 kg |
| t (metric ton) | 1,000 kg | 1,000 kg |
| gr (grain) | 1/7,000 lb | 64.79891 mg |
| oz t (troy ounce) | 480 grains | 31.1034768 g |
| ct (metric carat) | 200 mg | 0.2 g |
The calculation keeps 12 significant digits: the result shows up to 10 significant digits, and the factor line gives the full figure with thousands separators, such as 1 st = 6,350.29318 g. That is far more precision than any kitchen or bathroom scale can deliver.
Examples
1. Body weight in pounds and kilograms
| Pounds | Kilograms |
|---|---|
| 150 lb | 68.04 kg |
| 180 lb | 81.65 kg |
| 200 lb | 90.72 kg |
| 154.32 lb | 70 kg |
| 176.37 lb | 80 kg |
| 198.42 lb | 90 kg |
If a British source gives a weight as 11 st, that is 154 lb or 69.85 kg.
2. Following a recipe in grams
8 oz of cheese is 226.80 g, 4 oz is 113.40 g and a 2.5 lb roast is 1,133.98 g. Going the other way, a 250 g pack of butter is 8.82 oz and a 500 g bag of pasta is 1.10 lb.
3. Gold and gemstones
One troy ounce is 31.10 g, or 1.0971 ordinary ounces, so a troy ounce of gold weighs about 10% more than an ounce of flour. A 1 kg bar holds 32.15 troy ounces. A 1-carat diamond weighs 200 mg, and 1 g equals 5 carats.
Three ounces and three tons
The ounce (oz) on food packages is the avoirdupois ounce, 1/16 of a pound. The troy ounce (oz t) is a separate, heavier unit of 480 grains. The fluid ounce measures volume, not weight; use the volume converter for it. Tons are just as easy to mix up: a US ton is 2,000 lb (0.907 t), a long ton is 2,240 lb (1.016 t) and a metric ton, often spelled tonne, is 1,000 kg, or 2,204.62 lb. Strictly speaking, all of these are units of mass; in everyday language and on scales, mass is called weight.
Frequently asked questions
How many pounds are in a kilogram?
One kilogram is 2.20462262185 lb, usually rounded to 2.2046. To go from pounds to kilograms, multiply by 0.45359237: 10 lb = 4.54 kg.
Is there a quick way to convert kg to lb in my head?
Multiply by 2.2. For 70 kg that gives 154 lb, against the exact 154.32 lb, so the shortcut is within about 0.2%. For pounds to kilograms, divide by 2.2.
How many grams are in an ounce?
One avoirdupois ounce is 28.349523125 g, about 28.35 g. Sixteen ounces make one pound, which is 453.59 g.
What is a stone in pounds and kilograms?
A stone is 14 lb, exactly 6.35029318 kg. 12 st is 168 lb, and 75 kg is 11.81 st.
Is a troy ounce the same as a regular ounce?
No. A troy ounce is 31.10 g, a regular (avoirdupois) ounce is 28.35 g. Both contain whole numbers of the same grain: 480 grains in a troy ounce and 437.5 in an avoirdupois ounce. One pound equals 14.58 troy ounces.
What is the difference between a ton and a tonne?
In the US an unqualified ton is the short ton of 2,000 lb, equal to 0.90718474 t. A tonne (metric ton) is 1,000 kg, which is 1.1023 US tons. The long ton of 2,240 lb is 1.016 t.
Sources
Conversions use the exact definitions listed on this page and are rounded for display. For trade, shipping or medication doses, rely on the units and scales required by the applicable rules.