Metric conversion chart
1 inch = 2.54 cm, 1 pound = 0.4536 kg, 1 US gallon = 3.785 L, and °F = °C × 9/5 + 32. The tables below cover the metric prefixes and the factors for length, weight, volume, area and temperature, in both directions.
Metric prefixes
The same prefixes work with grams, liters and every other metric unit: a milligram is a thousandth of a gram, a kiloliter is 1,000 liters.
| Prefix | Symbol | Times the base unit | Example |
|---|---|---|---|
| kilo | k | 1,000 | 1 km = 1,000 m |
| hecto | h | 100 | 1 hm = 100 m |
| deca | da | 10 | 1 dam = 10 m |
| (base unit) | — | 1 | meter (m) |
| deci | d | 0.1 | 1 m = 10 dm |
| centi | c | 0.01 | 1 m = 100 cm |
| milli | m | 0.001 | 1 m = 1,000 mm |
| micro | µ | 0.000001 | 1 m = 1,000,000 µm |
Factors rounded to five significant figures. Linked rows open the converter with the exact factor.
Length
Weight
Volume (US)
Area
| Unit | Equals |
|---|---|
| 1 cm² | 0.155 in² |
| 1 m² | 10.764 ft² |
| 1 ha | 2.4711 ac |
| 1 km² | 0.3861 mi² |
| 1 in² | 6.4516 cm² |
| 1 ft² | 0.092903 m² |
| 1 ac | 0.40469 ha |
| 1 mi² | 2.59 km² |
Temperature
| °C | °F |
|---|---|
| −40 °C | −40 °F |
| −20 °C | −4 °F |
| −10 °C | 14 °F |
| 0 °C | 32 °F |
| 10 °C | 50 °F |
| 20 °C | 68 °F |
| 25 °C | 77 °F |
| 30 °C | 86 °F |
| 37 °C | 98.6 °F |
| 40 °C | 104 °F |
| 100 °C | 212 °F |
| 180 °C | 356 °F |
| 200 °C | 392 °F |
skalaconvert.com/charts/metric-conversion-chart/ — Reviewed on September 30, 2026 by the Skala Convert team
Reviewed on by the Skala Convert team
How does the metric system work?
Every unit is the base unit times a power of ten, and the prefix tells you which power. Kilo means 1,000, centi means a hundredth, milli a thousandth — for meters, grams and liters alike. Converting inside the system is moving the decimal point: 1.75 m is 175 cm is 1,750 mm. The order from large to small, kilo, hecto, deca, base, deci, centi, milli, is what school mnemonics like “King Henry Died By Drinking Chocolate Milk” are for.
US customary units have no such pattern — 12 inches to a foot, 3 feet to a yard, 1,760 yards to a mile, 16 ounces to a pound — which is why most conversions in practice are between the two systems, and why this chart is mostly factors.
Which of these factors are exact?
The US-to-metric ones in their definitions. Since 1959 the inch has been exactly 2.54 cm, the foot 0.3048 m, the yard 0.9144 m and the mile 1,609.344 m; the pound is exactly 0.45359237 kg; and the US gallon, defined as 231 cubic inches, comes out at exactly 3.785411784 L. The metric-to-US factors are their inverses — 1 kg = 2.20462… lb — and those never terminate, which is why the chart rounds them to five significant figures. For more digits, the linked rows open the converter for that pair, such as gallons to liters.
How do you convert temperatures?
With a formula rather than a factor, because the two scales start at different points: °F = °C × 9/5 + 32, and °C = (°F − 32) × 5/9. Water freezes at 0 °C and 32 °F and boils at 100 °C and 212 °F at sea level; the two scales cross at −40, where both read the same. Normal body temperature, 37 °C, is 98.6 °F. The Celsius to Fahrenheit converter handles any value.
Which approximations are good enough for everyday use?
A handful cover most situations. A meter is a little over 3 feet (3.28). A kilogram is about 2.2 pounds. A liter is slightly more than a US quart. A kilometer is about 0.6 of a mile, so a 10 km race is 6.2 miles. A 30 °C day is 86 °F. They are fine for a recipe, a road sign or a weather forecast; for anything you will build, measure or dose, use the exact factor.
Who defines these units?
The prefixes and the base units come from the International System of Units (SI), set out in the SI Brochure published by the International Bureau of Weights and Measures (BIPM). The General Conference on Weights and Measures still extends the list: in 2022 it added ronna (1027), quetta (1030), ronto and quecto for the very large and very small. On the US side, NIST Special Publication 811, the US guide to the SI, tabulates the conversion factors this chart uses, and NIST Handbook 44 — the reference for US weights-and-measures inspectors — defines the gallon as 231 cubic inches. The length and volume pages cover each unit in more depth.
Frequently asked questions
How many pounds are in a kilogram?
One kilogram is 2.20462 pounds. The pound is defined as exactly 0.45359237 kg, so the conversion from kilograms to pounds is its inverse and never ends in a clean decimal.
How many feet are in a meter?
One meter is 3.28084 feet, or 39.3701 inches. Going the other way is exact: one foot is 0.3048 m.
Is a liter bigger than a quart?
Slightly. One liter is 1.05669 US quarts, so a liter bottle holds about 5.7% more than a quart carton.
What is the difference between imperial and US customary units?
Length and weight match: the inch, foot, mile and pound are the same in both. Volume does not. The US gallon is 3.785 L and the imperial (UK) gallon is 4.546 L, and the fluid ounces differ too — 29.57 mL in the US, 28.41 mL in the UK. This chart uses US units.
How do you convert Celsius to Fahrenheit in your head?
Double the Celsius figure and add 30. It is close for everyday weather — 20 °C gives 70 °F against an exact 68 °F — and drifts further off at oven temperatures, where the exact formula, °C × 9/5 + 32, is worth using.