Weight Converter
Convert between kilograms, stone, pounds, ounces and more instantly.
The United Kingdom sits in a unique position when it comes to weight measurement. While shops sell food in grams and kilograms and official documents use the metric system, most people still talk about their body weight in stone and pounds. Ask anyone in the UK how much they weigh and you will almost certainly hear an answer like eleven stone four rather than seventy-two kilograms. Gyms display weight plates in kilograms, but members mentally convert to stone to track progress. Recipes from American websites list ingredients in ounces and pounds, while European sources use grams, and supermarket labels show both. This dual-system reality makes a reliable weight converter an everyday necessity.
Our free Weight Converter handles nine units covering both metric and imperial systems, including milligrams, grams, kilograms, metric tonnes, ounces, pounds, stone, US tons, and UK tons. Results update instantly as you type, and stone values are displayed in the traditional format of stone and pounds rather than awkward decimals. The quick conversions panel below the main tool provides one-click access to the most common UK conversions, letting you switch between kilograms and stone and pounds without any manual input. All calculations run entirely in your browser, so your data stays private and there is zero server delay.
Quick UK Conversions
How Weight Conversion Works
Weight conversion relies on fixed, internationally recognised ratios between units. Our converter uses a base-unit approach: every input is first converted to grams, then from grams to the target unit. Stone results are automatically formatted as stone and pounds for readability.
How to Use This Converter
- Enter an amount in the number field at the top. You can type any positive number, including decimals.
- Select the unit you are converting from using the "From" dropdown. Choose from milligram, gram, kilogram, tonne, ounce, pound, stone, US ton, or UK ton.
- Select the target unit using the "To" dropdown. The result updates instantly as you change either unit or the amount.
- Use the Swap button to reverse the conversion direction with one click. This is handy when you want to convert back and forth quickly.
- Copy the result by clicking the "Copy" button. The full conversion summary is copied to your clipboard, ready to paste into a message, document, or spreadsheet.
How It Works
The converter stores a conversion factor for each unit, representing how many grams one unit equals. When you enter a value, it is multiplied by the source unit's factor to produce grams, then divided by the target unit's factor to produce the result. For example, converting 10 stone to kilograms: 10 multiplied by 6,350.29 gives 63,502.9 grams, divided by 1,000 gives 63.503 kg. When the target unit is stone, the converter calculates the total in stone, takes the whole number, and multiplies the remainder by 14 to express the leftover as pounds, giving results like 12 st 8.4 lbs. All arithmetic uses JavaScript floating-point precision and runs entirely in your browser with no server communication.
Common Conversions Reference
| From | To | Category |
|---|---|---|
| 1 kg | 2.205 lbs | Metric to Imperial |
| 1 stone | 6.350 kg | Imperial to Metric |
| 1 stone | 14 lbs | Imperial |
| 1 pound | 453.6 g | Imperial to Metric |
| 1 ounce | 28.35 g | Imperial to Metric |
| 1 kg | 35.274 oz | Metric to Imperial |
| 1 tonne | 1,000 kg | Metric |
| 1 US ton | 907.2 kg | Imperial to Metric |
| 1 UK ton | 1,016.0 kg | Imperial to Metric |
| 10 stone | 63.50 kg | Body Weight |
Frequently Asked Questions
How many kg are in a stone?
One stone equals exactly 6.35029 kilograms. To convert stone to kilograms, multiply the number of stone by 6.35029. For example, 10 stone equals 63.503 kg and 12 stone equals 76.204 kg. The stone is still widely used in the United Kingdom and Ireland for measuring body weight, even though shops and official records use metric units. This converter handles the calculation instantly so you never have to memorise the factor.
How do I convert kg to stone and pounds?
Divide the kilogram value by 6.35029 to get the total in stone as a decimal. Take the whole number part as the stone value. Multiply the decimal remainder by 14 to get the leftover pounds. For example, 80 kg divided by 6.35029 equals approximately 12.598 stone. The whole part is 12 stone. The remainder 0.598 multiplied by 14 gives 8.37 pounds, so 80 kg is 12 stone 8.4 lbs. Our converter does this automatically and always shows stone results in the traditional stone-and-pounds format.
Why does the UK use stone for body weight?
The stone has been a unit of weight in Britain since at least the fourteenth century, originally used in trade for wool and other commodities. Although the UK officially adopted the metric system for trade and commerce, stone remains deeply embedded in everyday culture for discussing personal body weight. Most people grew up hearing their parents and doctors use stone, and the habit has persisted across generations. It provides a convenient middle-ground figure that is neither as large as the pound count nor as unfamiliar as the kilogram count for many British people.
How many pounds are in a stone?
One stone equals exactly 14 pounds. This relationship has been fixed and legally standardised since 1835. To convert stone to pounds, multiply by 14. To convert pounds to stone, divide by 14. For example, 11 stone is 154 pounds and 150 pounds is 10 stone 10 lbs. This fixed ratio makes mental arithmetic fairly straightforward once you know the factor.
What is the difference between a US ton and a UK ton?
A US ton, also called a short ton, equals 2,000 pounds or approximately 907.185 kilograms. A UK ton, also called a long ton, equals 2,240 pounds or approximately 1,016.047 kilograms. The UK ton is about 12 percent heavier than the US ton. The metric tonne, used internationally, is exactly 1,000 kilograms and sits between the two. When reading shipping documents or recipes from different countries, always check which type of ton is being referenced to avoid costly errors.
How many grams are in an ounce?
One avoirdupois ounce equals approximately 28.3495 grams. This is the standard ounce used for food packaging, postal weights, and general measurement. There is also a troy ounce, used for precious metals like gold and silver, which is slightly heavier at 31.1035 grams. Our converter uses the avoirdupois ounce since it is the one encountered in everyday life. To convert ounces to grams, multiply by 28.3495. To go the other way, divide grams by 28.3495.
How accurate is this weight converter?
The converter uses internationally recognised conversion factors stored with full JavaScript floating-point precision (64-bit double). Results are displayed to up to eight significant figures, which exceeds the accuracy needed for cooking, fitness tracking, postal weighing, and most professional and scientific applications. All calculations run locally in your browser with no rounding shortcuts and no data sent to any server, so results are both precise and private.
