How do I convert a weight?
Enter a weight, pick the unit it is in and the unit you want, and the answer updates as you type. The result panel also shows the weight in kilograms, pounds, ounces, and stone.
- Converted weight
- 68.038856
150 pounds (lb) = 68.038856 kilograms (kg).
- Kilograms (kg)
- 68.038856
- Grams (g)
- 68,038.8555
- Pounds (lb)
- 150
- Ounces (oz)
- 2,400
- Pounds and ounces
- 150 lb 0 oz
- Stone and pounds
- 10 st 10 lb
Converted weight: 68.038856. 150 pounds (lb) = 68.038856 kilograms (kg).
How to calculate
Converts a weight from any unit to any other: milligrams, grams, kilograms, tons, ounces, pounds, stone, and grains.
Example with the default inputs (Weight 150, From pounds (lb), To kilograms (kg)): 150 pounds (lb) = 68.038856 kilograms (kg).
Method: converted = weight × (kilograms per "From" unit) ÷ (kilograms per "To" unit)
- Kilograms per unit come from the exact definitions in NIST SP 811: 1 lb = 0.45359237 kg, 1 oz = 1/16 lb, 1 grain = 1/7,000 lb, 1 US short ton = 2,000 lb, 1 metric ton = 1,000 kg, 1 UK long ton = 2,240 lb.
- 1 stone = 14 lb (UK Weights and Measures Act 1985).
- Ounces are avoirdupois ounces, the ounces of weight. Troy ounces (for precious metals) are a different unit.
- The answer shows at most 6 decimal places; the calculation keeps full precision.
Worked examples
Each example is checked against the calculator on every build.
- Weight 150, From pounds (lb), To kilograms (kg) gives Converted weight 68.038856, Pounds (lb) 150, Pounds and ounces 150 lb 0 oz, Stone and pounds 10 st 10 lb.Source: NIST SP 811 (2008) B.8: 1 lb = 0.45359237 kg exactly
- Weight 1, From kilograms (kg), To pounds (lb) gives Converted weight 2.204623, Ounces (oz) 35.273962, Pounds and ounces 2 lb 3.27 oz, Stone and pounds 0 st 2.2 lb.Source: NIST SP 811 (2008) B.8: 1 kg = 1 ÷ 0.45359237 lb
- Weight 10, From stone (st), To kilograms (kg) gives Converted weight 63.502932.Source: UK Weights and Measures Act 1985, Schedule 1: 1 stone = 14 lb
- Weight 1, From UK long tons (2,240 lb), To metric tons (t) gives Converted weight 1.016047.Source: NIST SP 811 (2008) B.8: 1 long ton = 2,240 lb = 1,016.0469088 kg
- Weight 1, From US short tons (2,000 lb), To pounds (lb) gives Converted weight 2,000.Source: NIST SP 811 (2008) B.8: 1 short ton = 2,000 lb
How it works
Every unit has an exact size in kilograms. The calculator turns the weight into kilograms, then into the unit you want:
converted = weight × (kilograms per "From" unit) ÷ (kilograms per "To" unit)
Kilograms per unit, all exact:
| Unit | Kilograms |
|---|---|
| microgram (µg) | 0.000000001 |
| milligram (mg) | 0.000001 |
| gram (g) | 0.001 |
| kilogram (kg) | 1 |
| metric ton (t) | 1,000 |
| grain (gr) | 0.45359237 ÷ 7,000 |
| ounce (oz) | 0.45359237 ÷ 16 = 0.028349523125 |
| pound (lb) | 0.45359237 |
| stone (st) | 14 × 0.45359237 = 6.35029318 |
| US short ton | 2,000 × 0.45359237 = 907.18474 |
| UK long ton | 2,240 × 0.45359237 = 1,016.0469088 |
The result panel also shows the weight in kilograms, grams, pounds, and ounces, and two mixed forms:
- Pounds and ounces: the whole pounds, then the rest × 16 in ounces, rounded to 0.01 oz. If the ounces round to 16.00, they count as one more pound.
- Stone and pounds: the weight in pounds rounded to 0.01 lb, then the whole stone (14 lb each), then the pounds left over.
Assumptions
- Ounces are avoirdupois ounces (1/16 lb), not troy ounces.
- The answer shows at most 6 decimal places; the calculation keeps full precision.
Worked examples by hand
150 lb to kg. 150 × 0.45359237 = 68.0388555 kg. In mixed forms: 150 lb 0 oz, and 150 ÷ 14 = 10 stone with 150 − 140 = 10 st 10 lb.
1 kg to lb. 1 ÷ 0.45359237 = 2.2046226218 lb. Whole pounds: 2; the rest is 0.2046226218 × 16 = 3.27 oz, so 2 lb 3.27 oz. In ounces: 2.2046226218 × 16 = 35.27396195 oz. In stone: 2.2 lb is less than 14 lb, so 0 st 2.2 lb.
10 stone to kg. 10 × 14 = 140 lb, and 140 × 0.45359237 = 63.5029318 kg.
1 long ton to metric tons. 2,240 × 0.45359237 = 1,016.0469088 kg, and 1,016.0469088 ÷ 1,000 = 1.0160469088 t.
1 short ton to pounds. A US short ton is 2,000 lb.
Other questions people ask
How many kilograms are in a pound?
1 pound is exactly 0.45359237 kg, by the international definition of 1959 (NIST SP 811). So 150 lb is 150 × 0.45359237 = 68.0388555 kg.
How many pounds are in a stone?
14. A stone is 14 lb (UK Weights and Measures Act 1985), which is 6.35029318 kg. 10 st 10 lb is 150 lb.
What is the difference between a short ton, a metric ton, and a long ton?
A US short ton is 2,000 lb (907.18474 kg), a metric ton or tonne is 1,000 kg, and a UK long ton is 2,240 lb (1,016.0469088 kg). In the US, "ton" means the short ton.
Is weight the same as mass?
In everyday use, yes. Scales show mass in kilograms or pounds, and this calculator converts between those units. In physics, weight is a force measured in newtons, which depends on gravity.
Is an ounce of gold the same as an ounce here?
No. This calculator uses the avoirdupois ounce, 1/16 lb (28.349523125 g). Gold and silver are weighed in troy ounces of 31.1034768 g.