Weight & Mass Converter

Convert between kilograms, pounds, stone, ounces, grams, tonnes, carats, troy ounces and more. This tool is useful for body weight, cooking, shipping, jewellery, study, engineering checks and quick metric-to-imperial conversions. Enter a value in any unit and the converter updates every other unit in real time, with reference tables and practical examples to help you check the result.

Convert weight / mass

Choose any input box, enter a value, and the calculator converts it through grams as the base unit. This keeps kg, lb, stone, ounces, tonnes, troy ounces and carats consistent across the page.

Quick references

Full conversion table

Enter a weight above to see all conversions.

Body weight quick-reference

Common body weights in kg, stone & lbs, and pounds.

kg	Stone & lbs	Pounds (lbs)	Note

Precious metals & troy weights

Troy weight is the standard for gold, silver, and gemstones — different from the everyday avoirdupois ounce.

Note: 1 troy ounce = 31.1035 g, but 1 avoirdupois ounce = 28.3495 g. Troy ounces are ~9.7% heavier. Always check which system is being used when buying or selling precious metals.

Real-world weight reference

From a grain of rice to the mass of the Earth.

Cooking weight guide

Common cooking measurements and ingredient weights.

Conversion formulas

How it works

This converter treats grams as the central base unit. When you enter a value, the page first converts that value into grams, then converts the gram value into every other unit. This avoids inconsistent chained conversions and keeps the results aligned across metric, imperial, US, troy and specialist mass units.

For example, if you enter kilograms, the calculator multiplies by 1,000 to get grams. It then divides the gram value by the gram equivalent of pounds, ounces, stones, tonnes, carats or any other selected unit. The same approach works in reverse: if you enter pounds, the calculator converts pounds into grams first, then into kilograms and all other units.

Formula used

For most weight and mass conversions, the calculator uses this two-step formula:

value in grams = input value × gram factor of input unit
converted value = value in grams ÷ gram factor of target unit

Common factors include: 1 kg = 1,000 g, 1 lb = 453.59237 g, 1 oz = 28.349523125 g, 1 stone = 6,350.29318 g, 1 metric tonne = 1,000,000 g, 1 troy ounce = 31.1034768 g and 1 metric carat = 0.2 g.

Worked example

Example: convert 70 kg to pounds

First convert kilograms into grams, then grams into pounds.

70 kg × 1,000 = 70,000 g
70,000 g ÷ 453.59237 = 154.3236 lb

So, 70 kg is about 154.3 lb.

Example: convert 11 stone to kilograms

One stone is 14 pounds, or about 6.35029318 kg.

11 st × 6.35029318 = 69.8532 kg

So, 11 stone is about 69.9 kg.

Common mistakes

Confusing pounds and stone

In UK body weight, stone and pounds are often written together. For example, 11 st 4 lb means 11 stone plus 4 pounds, not 11.4 stone.

Mixing troy ounces and normal ounces

A troy ounce is used for precious metals and is heavier than a normal avoirdupois ounce. Always check which ounce is being used.

Treating mass and volume as the same

Grams and millilitres are only directly equivalent for water under common conditions. Flour, sugar, oil and honey have different densities.

Rounding too early

Keep a few extra decimal places during a calculation, especially for jewellery, shipping, scientific or engineering work.

Common questions

Is weight the same as mass? ⌄

In everyday use, people often say weight when they mean mass. Scientifically, mass is the amount of matter, while weight is the force caused by gravity. This page is intended for everyday mass/weight unit conversions.

How many pounds are in a stone? ⌄

There are 14 pounds in 1 stone. For example, 11 stone is 154 pounds.

What is the difference between an ounce and a troy ounce? ⌄

A normal avoirdupois ounce is about 28.3495 g. A troy ounce is about 31.1035 g and is mainly used for precious metals such as gold and silver.

Can I convert grams to cups? ⌄

Not accurately without knowing the ingredient. Cups measure volume and grams measure mass, so the conversion depends on density. A cup of water weighs more than a cup of flour.

Sources, assumptions and disclaimer

This converter is designed for general everyday use, study, cooking estimates, body-weight reference and quick comparison. Conversion factors use widely accepted metric, imperial, avoirdupois and troy relationships. Results are rounded for readability and should be checked against official documentation for safety-critical or high-value uses.

Metric conversions: kilogram, gram, milligram, microgram and tonne conversions use decimal metric relationships.
Imperial/US conversions: pound, ounce, stone, long ton and short ton use standard avoirdupois relationships.
Troy conversions: troy ounce, troy pound, pennyweight and carat values are included because they are commonly used in jewellery, gemstones and precious metals.
Cooking references: cooking weights are approximate because ingredients have different densities and can vary depending on how they are packed or measured.
Body weight references: body-weight examples are for unit conversion only and should not be treated as medical guidance.