Weight Converter
Convert weight between pounds, ounces, stones, grams, kilograms, and metric tons.
What is Weight Converter?
The weight converter transforms any mass reading between the U.S. customary system (ounces, pounds, stones, short tons) and the metric system (mg, g, kg, metric tons).
Technically "weight" is a force and "mass" is what we are actually converting here — but in everyday American English "weight" wins.
Formula
All conversions use exact factors, with 1 lb = 0.45359237 kg being the defining equivalence since 1959:
- 1 oz = 1/16 lb = 28.349523125 g
- 1 stone (UK) = 14 lb = 6.35029318 kg
- 1 U.S. short ton = 2,000 lb = 907.18474 kg
- 1 metric ton (tonne) = 1,000 kg
Worked example
Convert 150 pounds:
- = 2,400 oz
- = 10.71 stones
- = 68.04 kg
- = 68,039 grams
How to use this calculator
- Enter the value you want to convert.
- Pick the starting unit.
- All eight units are shown simultaneously.
Frequently asked questions
What is the difference between a metric ton and a U.S. ton?
A metric ton (tonne) is 1,000 kg ≈ 2,204.6 lb. A U.S. "short" ton is 2,000 lb ≈ 907.2 kg. The U.K. also uses a "long" ton of 2,240 lb ≈ 1,016 kg (not included here — rare in modern use).
Do people still use stones?
Yes — body weight in the U.K. and Ireland is typically reported in stones and pounds. A British person might say they weigh "11 stone 6" meaning 160 lb.
Why is 1 pound exactly 0.45359237 kg?
That exact value was agreed to in 1959 by the U.S., UK, Canada, Australia, New Zealand, and South Africa to unify slightly different prior definitions. It is still the legal definition today.
What about troy ounces (gold, silver)?
Not included — those are precious-metal units. 1 troy ounce = 31.1034768 g (heavier than a regular ounce, which is 28.35 g).