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.

Conversion setup
Starting unit
Target unit
Enter any positive or negative number

Reference table for this category
FromToFactor / Formula

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).

FromToMultiply by
inchescentimeters2.54
feetmeters0.3048
yardsmeters0.9144
mileskilometers1.609344
centimetersinches0.393701
metersfeet3.28084
metersyards1.09361
kilometersmiles0.621371

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.

FromToMultiply by
ounces (oz)grams28.3495
pounds (lb)kilograms0.453592
stones (st)kilograms6.35029
short tons (US)metric tons0.907185
gramsounces0.035274
kilogramspounds2.20462
kilogramsstones0.157473
metric tonsshort 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.

FromToMultiply by
US fl ozmilliliters29.5735
US cupsmilliliters236.588
US pintsliters0.473176
US quartsliters0.946353
US gallonsliters3.78541
UK gallonsliters4.54609
litersUS gallons0.264172
litersUK gallons0.219969
litersUS cups4.22675

Temperature conversion table

Temperature scales use linear formulas rather than a single multiplier.

ConversionFormula
Celsius → Fahrenheit°F = °C × 9/5 + 32
Fahrenheit → Celsius°C = (°F − 32) × 5/9
Celsius → KelvinK = °C + 273.15

Common reference points:

°C°FMeaning
−40−40Scales intersect
032Water freezes
2068Room temperature
3798.6Body temperature
100212Water 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.

FromToMultiply by
sq inchessq centimeters6.4516
sq feetsq meters0.092903
sq yardssq meters0.836127
acressq meters4,046.86
acreshectares0.404686
sq milessq kilometers2.58999
sq centimeterssq inches0.155
sq meterssq feet10.7639
hectaresacres2.47105

Speed conversion table

FromToMultiply by
mphkm/h1.60934
km/hmph0.621371
m/skm/h3.6
knotskm/h1.852
knotsmph1.15078

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:

  1. Locate the row where the “From” column matches your starting unit and the “To” column matches your target unit.
  2. Multiply your numeric value by the factor in the third column.
  3. 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.

PrefixSymbolFactor
kilo-k1,000
hecto-h100
deka-da10
base unit1
deci-d0.1
centi-c0.01
milli-m0.001
micro-μ0.000001

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.
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