Metric Conversion Guide & Chart
A practical reference for converting metric units of length, weight, and volume — with formulas and imperial equivalents you can copy at a glance.
How the metric system works
The metric system (officially the SI, or International System of Units) is a decimal system built around three base units: the metre for length, the gram for mass, and the litre for volume. Every other unit is scaled by a power of ten using a prefix:
- kilo- = 1,000×
- hecto- = 100×
- deca- = 10×
- deci- = 0.1×
- centi- = 0.01×
- milli- = 0.001×
Converting inside the metric system is as simple as moving the decimal point. Converting to imperial units (feet, pounds, gallons) uses a fixed multiplier — the charts below list the ones you'll actually use.
Length
| From | To | Formula |
|---|---|---|
| 1 kilometre (km) | 0.621371 miles | × 0.621371 |
| 1 metre (m) | 3.28084 feet | × 3.28084 |
| 1 metre (m) | 1.09361 yards | × 1.09361 |
| 1 centimetre (cm) | 0.393701 inches | × 0.393701 |
| 1 millimetre (mm) | 0.0393701 inches | × 0.0393701 |
| 1 mile | 1.60934 kilometres | × 1.60934 |
| 1 foot | 0.3048 metres | × 0.3048 |
| 1 inch | 2.54 centimetres | × 2.54 |
Weight & Mass
| From | To | Formula |
|---|---|---|
| 1 tonne (t) | 1.10231 US tons | × 1.10231 |
| 1 kilogram (kg) | 2.20462 pounds | × 2.20462 |
| 1 gram (g) | 0.035274 ounces | × 0.035274 |
| 1 milligram (mg) | 0.0000353 ounces | × 0.0000353 |
| 1 pound (lb) | 0.453592 kilograms | × 0.453592 |
| 1 ounce (oz) | 28.3495 grams | × 28.3495 |
Volume
| From | To | Formula |
|---|---|---|
| 1 litre (L) | 0.264172 US gallons | × 0.264172 |
| 1 litre (L) | 0.219969 UK gallons | × 0.219969 |
| 1 litre (L) | 33.814 US fl oz | × 33.814 |
| 1 millilitre (mL) | 0.033814 US fl oz | × 0.033814 |
| 1 US gallon | 3.78541 litres | × 3.78541 |
| 1 UK gallon | 4.54609 litres | × 4.54609 |
| 1 cubic metre (m³) | 35.3147 cubic feet | × 35.3147 |
Quick conversion tips
- Kilometres to miles: multiply by 0.62 (or divide by 1.6) for a fast estimate.
- Kilograms to pounds: double the kilograms and add 10% — 10 kg ≈ 22 lb.
- Celsius to Fahrenheit: multiply by 1.8 and add 32.
- Litres to US gallons: divide by roughly 3.8.