About the Weight Converter
The Weight Converter instantly converts between all common metric and imperial weight units — from milligrams to metric tons. Whether you're checking body weight for a trip abroad, converting a recipe from ounces to grams, calculating shipping costs, or working with scientific measurements, this tool gives you precise results using internationally accepted conversion factors.
How Weight Conversions Work
All conversions are calculated relative to kilograms as the base unit:
Converted Value = Input × (From unit in kg ÷ To unit in kg)
For example, converting 5 pounds to kilograms: 5 × (0.453592 ÷ 1) = 2.268 kg.
Supported Units
- Metric: Milligrams (mg), Grams (g), Kilograms (kg), Metric Tons (t)
- Imperial / US: Ounces (oz), Pounds (lb)
- UK/Ireland: Stones (st)
Key Conversion Reference
- 1 ounce (oz) = 28.3495 grams
- 1 pound (lb) = 16 oz = 453.592 grams = 0.4536 kg
- 1 stone (st) = 14 lb = 6.3503 kg
- 1 kilogram (kg) = 1,000 g = 2.20462 lb = 35.274 oz
- 1 metric ton (t) = 1,000 kg = 2,204.62 lb ≈ 1.102 short tons
Mass vs. Weight: What's the Difference?
In everyday language, people use "weight" and "mass" interchangeably — but they are technically different. Mass is the amount of matter in an object, measured in kilograms (or grams, pounds, etc.). Weight is the gravitational force acting on that mass, measured in Newtons. On the Moon, your mass is the same as on Earth, but your weight is about 1/6th as much. For practical conversions in daily life, cooking, shipping, and fitness, mass units are what matter — and this converter handles all of them.
The Stone: A UK Weight Unit
The stone is a unit of mass equal to 14 pounds (approximately 6.35 kg). It's commonly used in the United Kingdom and Ireland for expressing body weight — for example, "I weigh 11 stone 4 lbs" means 158 lb or about 71.7 kg. The stone is rarely used outside these countries but remains standard on UK bathroom scales.
Real-World Uses
- Fitness & health — converting body weight between kg and lb when tracking progress internationally
- Cooking & baking — converting recipes between ounces/cups (US) and grams (metric)
- Shipping & logistics — calculating package weights in different unit systems for carriers
- Science & medicine — dosage calculations often require converting between mg and g or kg
- Agriculture & trade — commodity weights measured in tons, kg, or lb depending on market
- Travel — airline baggage limits are in kg; US travelers may need to convert from lb
For other common travel conversions, see the Length Converter for distances and heights, and the Temperature Converter for weather forecasts.
Frequently Asked Questions
How do you convert kilograms to pounds?
Multiply kilograms by 2.20462. Example: 10 kg × 2.20462 = 22.046 lb. To reverse, divide pounds by 2.20462: 22.046 lb ÷ 2.20462 = 10 kg.
How do you convert pounds to kilograms?
Divide pounds by 2.20462 (or multiply by 0.453592). Example: 150 lb × 0.453592 = 68.04 kg. This is one of the most common conversions for body weight when traveling between the US and metric countries.
How many grams are in a pound?
There are exactly 453.592 grams in one pound. So 1 oz = 28.3495 g, 1 lb = 453.592 g, and 1 kg = 2.20462 lb = 35.274 oz.
How many ounces are in a kilogram?
There are approximately 35.274 ounces in one kilogram. For cooking, 1 oz ≈ 28.35 g and 1 lb ≈ 454 g.
What is a stone in pounds and kilograms?
A stone (st) equals exactly 14 pounds (lb) or approximately 6.3503 kilograms. The stone unit is commonly used in the UK and Ireland for expressing body weight. For example, 11 stone = 154 lb = 69.85 kg.
What is the difference between mass and weight?
Mass is the amount of matter in an object, measured in kilograms (kg). Weight is the force of gravity acting on that mass, measured in Newtons (N). In everyday use, people use 'weight' when they actually mean mass — saying 'I weigh 70 kg' really means 'my mass is 70 kg.' The distinction matters in science and physics, but for practical conversions, mass units (kg, lb, g) are what this converter uses.
Can I convert milligrams to tons?
Yes. The Weight Converter supports milligrams (mg), grams (g), kilograms (kg), metric tons (t), ounces (oz), pounds (lb), and stones (st). To convert mg to metric tons: 1 metric ton = 1,000 kg = 1,000,000 g = 1,000,000,000 mg.
How many pounds is 100 kilograms?
100 kg × 2.20462 = 220.46 pounds. As a quick mental estimate, multiply kg by 2.2 for an approximate pound equivalent.