What is a Weight Converter?
A weight converter (technically a mass converter) is a tool that transforms measurements from one unit of mass to another. Mass is the amount of matter in an object, and it remains constant regardless of location.
This converter supports both metric units (kilograms, grams, milligrams, metric tons) and imperial units (pounds, ounces, stones), along with US and UK tons, making it perfect for cooking, shipping, body weight tracking, and scientific calculations.
How Does Weight Conversion Work?
Weight conversion uses fixed ratios between units:
- Convert to base unit: The input value is converted to kilograms (the SI base unit for mass).
- Convert to target unit: The kilogram value is then converted to the desired output unit.
- Apply conversion factor: Each unit has a defined relationship to the kilogram.
Conversion Formulas
1 kilogram (kg) = 1,000 grams
1 gram (g) = 1,000 milligrams
1 metric ton (t) = 1,000 kilograms
Imperial Units:
1 pound (lb) = 16 ounces = 0.45359237 kg (exact)
1 ounce (oz) = 28.349523125 grams (exact)
1 stone (st) = 14 pounds = 6.35029318 kg
1 US ton = 2,000 pounds = 907.18474 kg
1 UK ton = 2,240 pounds = 1,016.0469088 kg
Common Weight Conversions
- Kilograms to Pounds: Multiply by 2.20462 (1 kg = 2.20462 lb)
- Pounds to Kilograms: Multiply by 0.453592 (1 lb = 0.453592 kg)
- Ounces to Grams: Multiply by 28.3495 (1 oz = 28.3495 g)
- Grams to Ounces: Divide by 28.3495 (1 g = 0.035274 oz)
- Stone to Kilograms: Multiply by 6.35029 (1 st = 6.35029 kg)
Mass vs Weight
Mass is the amount of matter in an object. It's measured in kilograms or pounds and stays constant everywhere.
Weight is the force of gravity on that mass. Your mass is the same on Earth and the Moon, but your weight on the Moon is only 1/6 of your Earth weight due to lower gravity.
In everyday usage, people use "weight" when they technically mean "mass." This converter handles mass units, which is what scales measure.
Frequently Asked Questions
How many pounds are in a kilogram?
There are approximately 2.20462 pounds in 1 kilogram. For quick mental math, you can use 2.2 as an approximation. For example, 50 kg × 2.2 = 110 pounds.
How do I convert ounces to grams?
Multiply the ounce value by 28.3495. For cooking, a common approximation is 1 oz ≈ 30 grams. For precise measurements (like in baking or science), use the exact factor.
What is a stone in weight?
A stone is a British unit equal to 14 pounds or about 6.35 kg. It's commonly used in the UK and Ireland for body weight. For example, "10 stone" means 140 pounds or 63.5 kg.
Why are there different types of tons?
The US (short) ton equals 2,000 pounds, while the UK (long) ton equals 2,240 pounds. The metric ton (tonne) equals 1,000 kg (2,204.6 lb). Always specify which ton you mean to avoid confusion.
How accurate is this converter?
This converter uses exact international definitions from NIST and BIPM. Results are accurate to 8 significant figures, more than sufficient for any practical application including scientific work.