Last updated: April 2026 · Reviewed by Calculatormatics Editorial Team

Weight Converter

A free weight converter (mass converter) covering nine common units across the metric and imperial systems: milligram, gram, kilogram, metric ton, ounce, pound, stone, US short ton, and UK long ton. Enter a value in any unit and the calculator returns the equivalent in every other instantly. Conversions use exact factors — 1 lb = 453.592 g, 1 oz = 28.3495 g, 1 stone = 14 lbs = 6,350.29 g, 1 US ton = 2,000 lbs, 1 UK ton = 2,240 lbs, 1 metric ton = 1,000 kg — so results are precise rather than rounded approximations. The calculator uses the gram as its internal base unit, converting your input to grams first and then to the target, which guarantees consistent results across any pair. Useful for cooking conversions (US recipes in ounces vs European recipes in grams), body weight (metric kg vs UK stones+lbs vs US lbs), shipping weight calculations (where short ton vs long ton vs metric tonne genuinely differ), nutrition labels in mg, gym plate calculations, and any other situation where the source and target use different unit systems. Pick a starting unit and enter a value below.

How to Convert Weight Units

Weight (or mass) conversion follows the same base-unit method as length conversion: every unit is expressed as a multiple of grams, so converting between any two units requires two multiplications — one to convert to grams, one to convert from grams to the target unit.

Result = Input × (From factor in grams / To factor in grams)

Weight Unit Reference Table

Common Weight Conversions

The kg-to-lb conversion is by far the most common, particularly for body weight. Here are the most useful reference values:

Body Weight: kg vs. lbs vs. stones

Different countries use different units for body weight. The US uses pounds (lbs), most of the world uses kilograms (kg), and the UK and Ireland traditionally use stones and pounds (e.g., "11 stone 4 lbs"). For medical purposes, kilograms are the universal standard — BMI, drug dosages, and clinical measurements all use kg. After converting your weight, you can check your body mass index with the BMI Calculator or estimate daily calorie needs with the Calorie Calculator.

Worked Example: Convert 70 kg to Pounds

1 pound is exactly 0.45359237 kilograms. To convert kilograms to pounds, divide by this factor (or equivalently, multiply by 2.20462):

Step 1: Apply the conversion
  70 kg ÷ 0.45359237 = 154.32 lb

Step 2: Verify by reversing
  154.32 lb × 0.45359237 = 69.9998 kg ≈ 70 kg ✓

So 70 kg = 154.32 pounds. A useful quick approximation for kg → lb is to multiply by 2.2, which gets within 0.2% for everyday values.

Frequently Asked Questions