Weight Converter

How to Use This Calculator

1. Enter the weight or mass value.
2. Select the source unit (e.g. kilograms).
3. Select the target unit (e.g. pounds).
4. The conversion result is shown instantly.

Formula

Example

Frequently Asked Questions

• How many pounds are in a kilogram? ▼
  One kilogram equals exactly 2.20462262185 pounds. For everyday use, 1 kg ≈ 2.205 lb is accurate enough. The conversion factor stems from the exact definition: 1 pound = 0.45359237 kg exactly (established in 1959), so 1 kg = 1/0.45359237 ≈ 2.20462 lb. Practical examples: 70 kg = 154.3 lb (typical adult); 100 kg = 220.5 lb; 5 kg ≈ 11 lb. A quick mental shortcut: multiply kilograms by 2.2 to get approximate pounds. Do not confuse kilograms (kg) with kiloponds or kilograms-force — kg is a unit of mass, not force. In the US customary system, the pound is a unit of both mass and force (weight), which can cause confusion in physics contexts where mass and weight are distinguished.
• How many grams are in an ounce? ▼
  One avoirdupois ounce equals exactly 28.349523125 grams. For quick cooking estimates, use 28.35 g per ounce. Examples: 2 oz = 56.7 g; 4 oz (quarter pound) = 113.4 g; 8 oz (half pound) = 226.8 g; 16 oz (one pound) = 453.6 g. An important distinction: the troy ounce (used for precious metals like gold and silver) equals 31.1035 g — about 10% heavier than the avoirdupois ounce. When you see "1 oz gold," that is a troy ounce. The fluid ounce is a volume measurement (29.57 ml in US, 28.41 ml in UK), completely different from the weight ounce. Always clarify which ounce is meant in recipes, pharmacy, or commodity contexts.
• How many pounds are in a stone? ▼
  One stone equals exactly 14 pounds = 6.35029318 kg. The stone is used almost exclusively in the UK and Ireland for measuring body weight. For example, a person weighing 12 stone = 168 pounds = 76.2 kg; 10 stone = 140 lb = 63.5 kg. To convert stone to kg, multiply by 6.35; to convert to pounds, multiply by 14. In most other countries, body weight is expressed in kilograms. The stone has no equivalent in the US system — Americans use pounds only. If you see a British person's weight stated as "11 stone 4," that means 11 × 14 + 4 = 158 pounds = 71.7 kg. The stone derives from the old practice of weighing goods using actual stones as counterweights.
• What is the difference between mass and weight? ▼
  Mass is the amount of matter in an object, measured in kilograms (SI) or pounds-mass. It is constant regardless of location. Weight is the gravitational force acting on that mass, equal to mass × gravitational acceleration (W = mg). On Earth, g ≈ 9.81 m/s², so a 70 kg person weighs 70 × 9.81 = 686.7 Newtons. On the Moon (g ≈ 1.62 m/s²), the same person weighs only 113.4 N — but their mass is still 70 kg. In everyday language "weight" and "mass" are used interchangeably because we live on Earth where g is nearly constant. In science and engineering, the distinction matters: scales measure weight (force) but display mass (assuming Earth's gravity). Bathroom scales would show incorrect readings on the Moon or on Mars (g ≈ 3.72 m/s²).
• How do I convert ounces to grams for cooking? ▼
  Multiply ounces by 28.3495 to get grams. Quick reference: 1 oz = 28.35 g, 2 oz = 56.7 g, 4 oz = 113.4 g, 8 oz = 226.8 g, 12 oz = 340.2 g, 16 oz (1 lb) = 453.6 g. For baking, precision matters — a kitchen scale is more accurate than volume cups. If your recipe uses US cups, convert to grams using ingredient-specific densities: 1 cup flour ≈ 125 g, 1 cup sugar ≈ 200 g, 1 cup butter ≈ 227 g. Do not confuse fluid ounces (volume, 1 fl oz = 29.57 ml) with weight ounces (mass, 1 oz = 28.35 g). Water is almost the only ingredient where 1 fl oz ≈ 1 oz by weight, because its density is approximately 1 g/ml.

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