Metric Conversion Chart
Complete reference tables for converting between metric (SI) and imperial/US customary units across all common measurement categories.
Length Conversions
| Metric | Imperial/US | Factor |
|---|---|---|
| 1 millimeter (mm) | 0.03937 inches | × 0.03937 |
| 1 centimeter (cm) | 0.3937 inches | × 0.3937 |
| 1 meter (m) | 3.28084 feet | × 3.28084 |
| 1 meter (m) | 1.09361 yards | × 1.09361 |
| 1 kilometer (km) | 0.62137 miles | × 0.62137 |
| 1 inch (in) | 2.54 cm | × 2.54 |
| 1 foot (ft) | 30.48 cm | × 30.48 |
| 1 yard (yd) | 0.9144 m | × 0.9144 |
| 1 mile (mi) | 1.60934 km | × 1.60934 |
Weight / Mass Conversions
| From | To | Factor |
|---|---|---|
| 1 milligram (mg) | 0.000035274 oz | × 0.000035274 |
| 1 gram (g) | 0.035274 oz | × 0.035274 |
| 1 kilogram (kg) | 2.20462 lbs | × 2.20462 |
| 1 kilogram (kg) | 35.274 oz | × 35.274 |
| 1 metric ton (t) | 2,204.62 lbs | × 2204.62 |
| 1 ounce (oz) | 28.3495 g | × 28.3495 |
| 1 pound (lb) | 453.592 g | × 453.592 |
| 1 pound (lb) | 0.453592 kg | × 0.453592 |
| 1 stone (st) | 6.35029 kg | × 6.35029 |
| 1 US ton | 907.185 kg | × 907.185 |
Volume Conversions
| From | To | Factor |
|---|---|---|
| 1 milliliter (mL) | 0.033814 fl oz (US) | × 0.033814 |
| 1 liter (L) | 33.814 fl oz (US) | × 33.814 |
| 1 liter (L) | 0.26417 gallons (US) | × 0.26417 |
| 1 liter (L) | 4.22675 cups (US) | × 4.22675 |
| 1 fluid ounce (US) | 29.5735 mL | × 29.5735 |
| 1 cup (US) | 236.588 mL | × 236.588 |
| 1 pint (US) | 473.176 mL | × 473.176 |
| 1 quart (US) | 946.353 mL | × 946.353 |
| 1 gallon (US) | 3.78541 liters | × 3.78541 |
Temperature Conversions
Celsius → Fahrenheit
°F = (°C × 9/5) + 32
0°C = 32°F (freezing)
20°C = 68°F (room temp)
37°C = 98.6°F (body)
100°C = 212°F (boiling)
Fahrenheit → Celsius
°C = (°F − 32) × 5/9
32°F = 0°C
72°F = 22.2°C
98.6°F = 37°C
212°F = 100°C
Celsius → Kelvin
K = °C + 273.15
−273.15°C = 0 K (absolute zero)
0°C = 273.15 K
25°C = 298.15 K
100°C = 373.15 K
SI Prefixes Reference
| Prefix | Symbol | Factor |
|---|---|---|
| tera- | T | 10¹² |
| giga- | G | 10⁹ |
| mega- | M | 10⁶ |
| kilo- | k | 10³ |
| hecto- | h | 10² |
| deca- | da | 10¹ |
| deci- | d | 10⁻¹ |
| centi- | c | 10⁻² |
| milli- | m | 10⁻³ |
| micro- | μ | 10⁻⁶ |
| nano- | n | 10⁻⁹ |
Frequently Asked Questions
What is the metric system?
The metric system (International System of Units / SI) is a decimal-based measurement system used by most countries worldwide. It uses base units like meters (length), grams (mass), and liters (volume), with prefixes (kilo-, centi-, milli-) to denote multiples or fractions.
Why does the US use imperial units?
The US inherited the British Imperial system during colonial times. While the UK has largely metricated, the US retains customary units for everyday use (miles, pounds, Fahrenheit) despite using metric in science, medicine, and military contexts.
How do I convert Celsius to Fahrenheit?
Multiply Celsius by 9/5, then add 32. Formula: °F = (°C × 9/5) + 32. For example, 25°C = (25 × 1.8) + 32 = 77°F.
What is the difference between metric and imperial?
Metric uses powers of 10 (1 km = 1,000 m = 100,000 cm) making calculations straightforward. Imperial uses irregular ratios (1 mile = 5,280 feet = 63,360 inches), which are harder to compute mentally.
How many countries use the metric system?
Approximately 195 countries officially use the metric system. Only the United States, Myanmar, and Liberia have not fully adopted it as their primary measurement system.
What are SI prefixes?
SI prefixes indicate powers of 10: kilo- (1,000), hecto- (100), deca- (10), deci- (0.1), centi- (0.01), milli- (0.001), micro- (0.000001). For example, 1 kilometer = 1,000 meters.