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Approximate Conversions from U.S. Customary Measures to Metric
The numerical value of the units in the When You Know column are multiplied by the approximate unit conversion factor found in the Multiply By column to obtain a numerical value for the units listed in the To Find Column. For example:
| When You Know | Multiply By | To Find |
|---|---|---|
| 20 yd | 0.91 | approximately 18.2 m |
Length
| Symbol | When You Know | Multiply By | To Find | Symbol |
|---|---|---|---|---|
| in | inch | 2.54 | centimeter | cm |
| ft | foot | 30.48 | centimeter | cm |
| yd | yard | 0.91 | meter | m |
| mi | mile | 1.61 | kilometer | km |
Area
| Symbol | When You Know | Multiply By | To Find | Symbol |
|---|---|---|---|---|
| in² | square inch | 6.45 | square centimeter | cm² |
| ft² | square foot | 0.09 | square meter | m² |
| yd² | square yard | 0.84 | square meter | m² |
| mi² | square mile | 2.59 | square kilometer | km² |
| acre | 0.41 | hectare | ha |
Mass (weight)
| Symbol | When You Know | Multiply By | To Find | Symbol |
|---|---|---|---|---|
| oz | ounce | 28.35 | gram | g |
| lb | pound | 0.45 | kilogram | kg |
| short ton (2000 lb) | 0.91 | metric ton | t |
Volume
| Symbol | When You Know | Multiply By | To Find | Symbol |
|---|---|---|---|---|
| tsp | teaspoon | 4.93 | milliliter | mL |
| Tbsp | tablespoon | 14.79 | milliliter | mL |
| in³ | cubic inch | 16.39 | milliliter | mL |
| fl oz | fluid ounce | 29.57 | milliliter | mL |
| c | cup | 0.24 | liter | L |
| pt | pint, liquid | 0.47 | liter | L |
| qt | quart, liquid | 0.95 | liter | L |
| gal | gallon | 3.79 | liter | L |
| ft³ | cubic foot | 0.03 | cubic meter | m³ |
| yd³ | cubic yard | 0.76 | cubic meter | m³ |
Temperature (exact)
| Symbol | When You Know | Calculation | To Find | Symbol |
|---|---|---|---|---|
| °F | degree Fahrenheit | subtract 32, then divide by 1.8 | degree Celsius | °C |
| °F | degree Fahrenheit | subtract 32, divide by 1.8, add 273.15 | Kelvin | K |
Metric to U.S. Customary Conversions
Unit conversion is a multi-step process that involves multiplication or division by a numerical factor; selection of the correct number of significant digits; and rounding. Accurate unit conversions are obtained by selecting an appropriate conversion factor (a ratio which converts one unit of measure into another without changing the quantity).
Note: These approximate conversion factors are published as NIST SP 365, Metric Conversion Card. Copies of this publication can be requested by contacting theSI [at] nist.gov (theSI[at]nist[dot]gov) or made using the OWM Contacts System.
Resources
Contacts
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Metric Program