How to use the weight converter
- Type or paste a number into the Value field.
- Pick the source unit from the From unit dropdown, such as kilograms or pounds.
- Read the converted values for all eight units in the result table below.
- Change the value or unit to convert weight again; results update instantly.
How the conversions work
This weight converter uses exact international definitions rather than rounded approximations. Every input is first converted to grams, then divided by each target unit's gram equivalent.
The core constants are:
- 1 pound = 0.45359237 kilograms exactly (international avoirdupois definition)
- 1 ounce = 1/16 pound = 28.349523125 grams
- 1 stone = 14 pounds = 6.35029318 kilograms
- 1 metric tonne = 1,000 kilograms
- 1 US short ton = 2,000 pounds = 907.18474 kilograms
For example, to convert 75 kilograms to pounds: multiply 75 by 1,000 to get 75,000 grams, then divide by 453.59237 grams per pound, yielding approximately 165.347 pounds.
Quick reference table
Use this table for common values when you need to convert weight quickly without entering numbers.
| Kilograms | Grams | Pounds | Ounces | Stones |
|---|---|---|---|---|
| 0.5 | 500 | 1.1023 | 17.637 | 0.0787 |
| 1 | 1,000 | 2.2046 | 35.274 | 0.1575 |
| 5 | 5,000 | 11.023 | 176.37 | 0.7874 |
| 10 | 10,000 | 22.046 | 352.74 | 1.5747 |
| 50 | 50,000 | 110.23 | 1,763.7 | 7.874 |
| 100 | 100,000 | 220.46 | 3,527.4 | 15.747 |
Values are rounded to four decimal places for readability. The tool itself preserves up to twelve significant digits.
Metric versus imperial mass units
The metric system uses powers of ten: 1,000 milligrams make a gram, and 1,000 grams make a kilogram. A metric tonne (spelled with a final "e" to distinguish it) equals 1,000 kilograms or one megagram.
The imperial and US customary systems use less regular ratios. Sixteen ounces make a pound, fourteen pounds make a stone, and 2,000 pounds make a US short ton. The UK historically used a long ton of 2,240 pounds, but this tool uses the US short ton because it is more common in everyday American commerce.
When you use a mass converter like this one, keep in mind that the stone is almost exclusively used in the United Kingdom and Ireland for measuring body weight. Most other countries express body mass in kilograms.
Common mistakes when converting weight
A frequent error is confusing the US short ton (2,000 lb) with the metric tonne (1,000 kg). They differ by about 9.1 percent: one metric tonne equals roughly 1.102 US short tons.
Another mistake is treating fluid ounces and weight ounces as interchangeable. Fluid ounces measure volume and depend on the liquid's density, while avoirdupois ounces measure mass. This weight converter only handles mass units.
Finally, rounding too early introduces errors. If you round 1 lb to 0.45 kg instead of using the exact 0.45359237 kg, a shipment of 10,000 pounds would be off by nearly 36 kilograms. Always compute with full precision and round only the final display value.
Practical uses for a mass converter
Cooks often need to switch between grams and ounces when following recipes from different countries. A recipe calling for 225 grams of flour translates to about 7.94 ounces.
Fitness tracking frequently involves stones and pounds in the UK, while gym equipment worldwide is labeled in kilograms. Someone who weighs 12 stone 4 pounds needs to know that equals roughly 78.02 kilograms for medical forms.
Shipping and logistics professionals convert between US tons and metric tonnes when calculating freight costs across borders. For related conversions, you might also find the kg to lbs tool or the pounds to ounces page useful for focused single-unit lookups.
Worked examples
Each result below was produced by the same code the tool runs, so you can check your own numbers against them.
| Example | Input | Result |
|---|---|---|
| Average adult body mass | Value: 70; From unit: kg | Kilograms: 70; Grams: 70,000; Milligrams: 70,000,000; Metric tonnes: 0.07; Pounds: 154.323583529; Ounces: 2,469.17733647; Stones: 11.0231131092; US tons: 0.077161791765 |
| One pound in metric | Value: 1; From unit: lb | Pounds: 1; Kilograms: 0.45359237; Grams: 453.59237; Milligrams: 453,592.369999999995; Metric tonnes: 0.00045359237; Ounces: 16; Stones: 0.071428571429; US tons: 0.0005 |
| Five hundred milligrams | Value: 500; From unit: mg | Milligrams: 500; Kilograms: 0.0005; Grams: 0.5; Metric tonnes: 5.000000e-7; Pounds: 0.001102311311; Ounces: 0.017636980975; Stones: 0.000078736522; US tons: 5.511557e-7 |
| Twelve stone four | Value: 12.2857; From unit: stone | Stones: 12.2857; Kilograms: 78.0177969215; Grams: 78,017.796921500005; Milligrams: 78,017,796.921499997377; Metric tonnes: 0.078017796922; Pounds: 171.9998; Ounces: 2,751.9968; US tons: 0.0859999 |
| Two US tons | Value: 2; From unit: ton | US tons: 2; Kilograms: 1,814.36948; Grams: 1,814,369.479999999981; Milligrams: 1,814,369,480; Metric tonnes: 1.81436948; Pounds: 4,000; Ounces: 64,000; Stones: 285.714285714 |
FAQ
What is the difference between mass and weight?
Mass is the amount of matter in an object and stays constant regardless of location. Weight is the force gravity exerts on that mass. In everyday language people use them interchangeably, and this weight converter handles mass units.
How many pounds are in a kilogram?
One kilogram equals exactly 2.20462262185 pounds. Conversely, one pound equals exactly 0.45359237 kilograms by international agreement.
Is a ton the same as a tonne?
No. A US short ton is 2,000 pounds (about 907.185 kg), while a metric tonne is exactly 1,000 kilograms (about 2,204.62 lb). They differ by roughly 9.1 percent.
Why does the stone equal 14 pounds?
The stone is a traditional British unit historically based on the weight of a standard stone used for weighing wool. Fourteen pounds became the legal standard in England in the 14th century and remains in use for body weight today.
Can I convert negative values?
Yes. While physical mass cannot be negative, the tool accepts negative numbers for mathematical or accounting purposes where signed differences are tracked.
Does this tool handle troy ounces?
No. Troy ounces (used for precious metals) differ from avoirdupois ounces. One troy ounce equals about 31.103 grams, while one avoirdupois ounce equals about 28.35 grams. This mass converter uses avoirdupois ounces.
Is my data sent to a server?
No. All calculations happen locally in your browser. Nothing you type is uploaded anywhere.
Reference pages
- Cooking conversions: cups to grams: baking ingredients with a chart and calculator.