Mass & Weight Converter
Convert between metric and imperial mass units — kilograms, pounds, grams, ounces, tonnes, and more
Unit Converter
Support fast conversion of various units including length, area, volume, weight, temperature, etc.
Common Units
Common Unit Conversions
Quick reference for frequently used unit conversions
Length
| From | To | Formula | Example |
|---|---|---|---|
| Inches (in) | Centimeters (cm) | in × 2.54 | 1 in = 2.54 cm |
| Feet (ft) | Meters (m) | ft × 0.3048 | 1 ft = 0.3048 m |
| Miles (mi) | Kilometers (km) | mi × 1.609 | 1 mi = 1.609 km |
| Meters (m) | Feet (ft) | m × 3.281 | 1 m = 3.281 ft |
| Kilometers (km) | Miles (mi) | km × 0.621 | 1 km = 0.621 mi |
Weight / Mass
| From | To | Formula | Example |
|---|---|---|---|
| Ounces (oz) | Grams (g) | oz × 28.35 | 1 oz = 28.35 g |
| Pounds (lb) | Kilograms (kg) | lb × 0.454 | 1 lb = 0.454 kg |
| Kilograms (kg) | Pounds (lb) | kg × 2.205 | 1 kg = 2.205 lb |
| Tons (t) | Tonnes (t) | t × 0.907 | 1 t = 0.907 tonnes |
Volume
| From | To | Formula | Example |
|---|---|---|---|
| Fl oz (US) | Milliliters (ml) | fl oz × 29.574 | 1 fl oz = 29.574 ml |
| Cups (US) | Milliliters (ml) | cup × 236.588 | 1 cup = 236.588 ml |
| Pints (US) | Liters (L) | pt × 0.473 | 1 pt = 0.473 L |
| Gallons (US) | Liters (L) | gal × 3.785 | 1 gal = 3.785 L |
| Liters (L) | Gallons (US) | L × 0.264 | 1 L = 0.264 gal |
Temperature
| From | To | Formula | Example |
|---|---|---|---|
| Celsius (°C) | Fahrenheit (°F) | (°C × 9/5) + 32 | 0°C = 32°F |
| Fahrenheit (°F) | Celsius (°C) | (°F - 32) × 5/9 | 32°F = 0°C |
| Celsius (°C) | Kelvin (K) | °C + 273.15 | 0°C = 273.15 K |
| Kelvin (K) | Celsius (°C) | K - 273.15 | 273.15 K = 0°C |
Area
| From | To | Formula | Example |
|---|---|---|---|
| Sq feet (ft²) | Sq meters (m²) | ft² × 0.0929 | 1 ft² = 0.0929 m² |
| Sq meters (m²) | Sq feet (ft²) | m² × 10.764 | 1 m² = 10.764 ft² |
| Acres | Hectares (ha) | acre × 0.405 | 1 acre = 0.405 ha |
| Hectares (ha) | Acres | ha × 2.471 | 1 ha = 2.471 acres |
Speed
| From | To | Formula | Example |
|---|---|---|---|
| MPH | KM/H | mph × 1.609 | 1 mph = 1.609 km/h |
| KM/H | MPH | km/h × 0.621 | 1 km/h = 0.621 mph |
| Knots | MPH | knots × 1.151 | 1 knot = 1.151 mph |
| M/S | KM/H | m/s × 3.6 | 1 m/s = 3.6 km/h |
Note: These are commonly used conversions with approximate values rounded for practical use. For precise conversions, use the calculator tool above.
Unit Conversion Reference Table
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What is Mass Conversion?
Mass conversion translates a weight measurement from one unit to another — kilograms to pounds, ounces to grams, and so on. It’s one of the most common conversions in daily life, from reading a recipe to checking luggage weight before a flight.
Three systems coexist. The metric system (kilograms, grams, tonnes) uses powers of ten and dominates globally and in science. The imperial/US customary system (pounds, ounces) is used in the United States. Chinese market units (jin, liang) still appear in markets across East Asia. None of these share round-number ratios, so a converter is needed to move between them.
Strictly speaking, mass and weight are different physical quantities — mass is the amount of matter, weight is the gravitational force on it. But for everyday purposes on Earth, they’re used interchangeably, and this converter handles both.
How to Convert Mass Units
Each mass unit has a conversion rate relative to a base unit (the kilogram). The formula:
result = value × (fromUnit rate) ÷ (toUnit rate)
Example — convert 10 pounds to kilograms:
10 lb = 10 × 0.453592 ÷ 1 = 4.536 kg
Example — convert 500 grams to ounces:
500 g = 500 × 0.001 ÷ 0.02835 = 17.637 oz
Key tip: The converter above applies these rates automatically — pick your two units and enter a value. Avoid the common mistake of confusing ounces (oz, weight) with fluid ounces (fl oz, volume).
Common Mass Conversions
| From | To | Multiply by |
|---|---|---|
| Pound (lb) | Kilogram (kg) | 0.4536 |
| Kilogram (kg) | Pound (lb) | 2.205 |
| Ounce (oz) | Gram (g) | 28.35 |
| US ton | Kilogram (kg) | 907.185 |
| Tonne (t) | US ton | 1.102 |
| Carat (ct) | Gram (g) | 0.2 |
Frequently Asked Questions
How many kilograms are in a pound?
One pound equals 0.45359237 kilograms, so to convert pounds to kilograms, multiply by 0.4536. For a quick estimate, divide pounds by 2.2 — 150 lb is about 68 kg. To go the other way, multiply kilograms by 2.205 to get pounds.
How many grams are in an ounce?
There are 28.3495 grams in one avoirdupois ounce (the ounce used for everyday weights). To convert ounces to grams, multiply by 28.35. Note that a troy ounce (used for precious metals like gold) is slightly heavier at 31.1035 grams.
What is the difference between a US ton and a metric tonne?
A US (short) ton is 2,000 pounds (907.185 kg). A metric tonne is 1,000 kilograms (2,204.62 pounds). The UK (long) ton is 2,240 pounds (1,016.05 kg). They differ because the US ton is based on the imperial pound while the tonne is based on the metric kilogram. Always check which "ton" a figure refers to.
What is a carat and what is it used for?
A carat is a unit of mass equal to 0.2 grams (200 milligrams), used almost exclusively for measuring gemstones and pearls. A 1-carat diamond weighs 0.2 g. The carat should not be confused with "karat" (kt), which measures gold purity (24 kt = pure gold) and is not a unit of mass.
What is the difference between mass and weight?
Mass is the amount of matter in an object, measured in kilograms, and it stays the same everywhere. Weight is the force of gravity on that mass, measured in newtons or pounds-force, and it changes with gravity — you weigh less on the Moon. In everyday use, "weight" and "mass" are used interchangeably, which is why scales show kilograms (a mass unit) even though they measure weight.