Unit Conversion Table
Whether you are scaling a recipe from cups to milliliters, checking a car’s fuel economy in different units, or reading engineering drawings, the right conversion factor saves time and prevents mistakes. A unit conversion table collects the most commonly used factors in one reference so you can convert by simple multiplication.
Length conversion table
Length is the most frequently converted category, bridging the metric system (millimeters, meters, kilometers) and the imperial system (inches, feet, yards, miles).
| From | To | Multiply by |
|---|---|---|
| inches | centimeters | 2.54 |
| feet | meters | 0.3048 |
| yards | meters | 0.9144 |
| miles | kilometers | 1.609344 |
| centimeters | inches | 0.393701 |
| meters | feet | 3.28084 |
| meters | yards | 1.09361 |
| kilometers | miles | 0.621371 |
Example: A room is 12 feet long. 12 × 0.3048 = 3.658 meters.
Weight and mass conversion table
Mass conversions matter in cooking, shipping, and science. One key relationship to remember: 1 kilogram = 2.20462 pounds.
| From | To | Multiply by |
|---|---|---|
| ounces (oz) | grams | 28.3495 |
| pounds (lb) | kilograms | 0.453592 |
| stones (st) | kilograms | 6.35029 |
| short tons (US) | metric tons | 0.907185 |
| grams | ounces | 0.035274 |
| kilograms | pounds | 2.20462 |
| kilograms | stones | 0.157473 |
| metric tons | short tons (US) | 1.10231 |
Volume conversion table
Volume units differ noticeably between US and UK systems. A US gallon holds 3.785 liters; a UK (imperial) gallon holds 4.546 liters – about 20 % more.
| From | To | Multiply by |
|---|---|---|
| US fl oz | milliliters | 29.5735 |
| US cups | milliliters | 236.588 |
| US pints | liters | 0.473176 |
| US quarts | liters | 0.946353 |
| US gallons | liters | 3.78541 |
| UK gallons | liters | 4.54609 |
| liters | US gallons | 0.264172 |
| liters | UK gallons | 0.219969 |
| liters | US cups | 4.22675 |
Temperature conversion table
Temperature scales use linear formulas rather than a single multiplier.
| Conversion | Formula |
|---|---|
| Celsius → Fahrenheit | °F = °C × 9/5 + 32 |
| Fahrenheit → Celsius | °C = (°F − 32) × 5/9 |
| Celsius → Kelvin | K = °C + 273.15 |
Common reference points:
| °C | °F | Meaning |
|---|---|---|
| −40 | −40 | Scales intersect |
| 0 | 32 | Water freezes |
| 20 | 68 | Room temperature |
| 37 | 98.6 | Body temperature |
| 100 | 212 | Water boils |
Area conversion table
Area factors are simply the squares of the corresponding length factors – but the resulting numbers are less intuitive, so a table is especially handy.
| From | To | Multiply by |
|---|---|---|
| sq inches | sq centimeters | 6.4516 |
| sq feet | sq meters | 0.092903 |
| sq yards | sq meters | 0.836127 |
| acres | sq meters | 4,046.86 |
| acres | hectares | 0.404686 |
| sq miles | sq kilometers | 2.58999 |
| sq centimeters | sq inches | 0.155 |
| sq meters | sq feet | 10.7639 |
| hectares | acres | 2.47105 |
Speed conversion table
| From | To | Multiply by |
|---|---|---|
| mph | km/h | 1.60934 |
| km/h | mph | 0.621371 |
| m/s | km/h | 3.6 |
| knots | km/h | 1.852 |
| knots | mph | 1.15078 |
Example: A speed limit of 60 mph equals 60 × 1.60934 ≈ 96.6 km/h.
How do you use a unit conversion table?
Every conversion follows the same three-step process:
- Locate the row where the “From” column matches your starting unit and the “To” column matches your target unit.
- Multiply your numeric value by the factor in the third column.
- Round the result to the decimal precision you need.
To convert in the opposite direction, use the inverse factor – divide 1 by the multiplier listed, or find the matching reverse row in the table. For instance, since 1 foot = 0.3048 meters, then 1 meter = 1 / 0.3048 ≈ 3.28084 feet.
Metric prefixes cheat sheet
The metric system scales by factors of 1,000. Knowing the prefix chain lets you convert between any two metric units without a table.
| Prefix | Symbol | Factor |
|---|---|---|
| kilo- | k | 1,000 |
| hecto- | h | 100 |
| deka- | da | 10 |
| base unit | – | 1 |
| deci- | d | 0.1 |
| centi- | c | 0.01 |
| milli- | m | 0.001 |
| micro- | μ | 0.000001 |
Example: 3.5 kilometers = 3,500 meters = 350,000 centimeters. Move the decimal point three places left for each step down the table.
Frequently Asked Questions
How do I convert units without a calculator?
Multiply your value by the conversion factor listed in the table. For instance, to convert 5 miles to kilometers: 5 × 1.609344 = 8.047 km.
What is the difference between metric and imperial units?
The metric system is based on powers of 10 – 1,000 millimeters in a meter, 1,000 meters in a kilometer. The imperial system uses fixed ratios: 12 inches in a foot, 3 feet in a yard, 5,280 feet in a mile.
Why are some conversion factors exact and others approximate?
Certain conversions are defined by international treaty. For example, 1 inch equals exactly 2.54 cm by definition. Other factors are derived from these definitions and carry more decimal places.
Which countries still use imperial units?
The United States, Liberia, and Myanmar primarily use customary or imperial measurements. The United Kingdom uses a mix of metric and imperial in everyday life.
What is the quickest way to estimate Fahrenheit from Celsius?
Double the Celsius value and add 30. For 20 °C you get roughly 70 °F – the exact answer is 68 °F. The shortcut works well for values between 0 °C and 40 °C.
How many milliliters are in one US fluid ounce?
One US fluid ounce equals 29.5735 mL. For everyday rounding, 30 mL per fluid ounce is a practical approximation.
Is a US gallon the same as a UK gallon?
No. A US gallon holds 3.785 liters, while a UK (imperial) gallon holds 4.546 liters – roughly 20 % more. Always check which gallon a source means.
What is the formula to convert Celsius to Kelvin?
Add 273.15 to the Celsius value. For example, 25 °C + 273.15 = 298.15 K. The Kelvin scale starts at absolute zero and uses the same degree size as Celsius.