| APPROXIMATE CONVERSIONS TO SI UNITS | APPROXIMATE CONVERSIONS FROM SI UNITS | |||||||
| Symbol | When You Know | Multiply By | To Find | Symbol | When You Know | Multiply By | To Find | Symbol |
| LENGTH | LENGTH | |||||||
| in | inches | 25.4 | millimeters | mm | millimeters | 0.039 | inches | in |
| ft | feet | 0.305 | meters | m | meters | 3.28 | feet | ft |
| yd | yards | 0.914 | meters | m | meters | 1.09 | yards | yd |
| mi | miles | 1.61 | kilometers | km | kilometers | 0.621 | miles | mi |
| AREA | AREA | |||||||
| in2 | square inches | 645.2 | square millimeters | mm2 | square millimeters | 0.0016 | square inches | in2 |
| ft2 | square feet | 0.093 | square meters | m2 | square meters | 10.764 | square feet | ft2 |
| yd2 | square yards | 0.836 | square meters | m2 | square meters | 1.195 | square yards | ac |
| ac | acres | 0.405 | hectares | ha | hectares | 2.47 | acres | mi2 |
| mi2 | square miles | 2.59 | square kilometers | km2 | square kilometers | 0.386 | square miles | |
| VOLUME | VOLUME | |||||||
| fl oz | fluid ounces | 29.57 | milliliters | ml | milliliters | 0.034 | fluid ounces | fl oz |
| gal | gallons | 3.785 | liters | l | liters | 0.264 | gallons | gal |
| ft3 | cubic feet | 0.028 | cubic meters | m3 | cubic meters | 35.71 | cubic feet | ft3 |
| yd3 | cubic yards | 0.765 | cubic meters | m3 | cubic meters | 1.307 | cubic yard | yd3 |
| NOTE: Volumes greater than 1000 l shall be shown in m3 | ||||||||
| MASS | MASS | |||||||
| oz | ounces | 28.35 | grams | g | grams | 0.035 | ounces | oz |
| lb | pounds | 0.454 | kilograms | kg | kilograms | 2.202 | pounds | lb |
| T | short tons (2000 lb) | 0.907 | megagrams | Mg | megagrams | 1.103 | short tons (2000 lb) | T |
| TEMPERATURE(exact) | TEMPERATURE(exact) | |||||||
| °F | Fahrenheit temperature | 5(F-32)/9 or (F-32)/1.8 | Celcius temperature | °C | Celcius temperature | 1.8C +32 | Fahrenheit temperature | °F |
| ILLUMINATION | ILLUMINATION | |||||||
| fc | foot-candles | 10.76 | lux | l | lux | 0.0929 | foot-candles | fc |
| fl | foot-Lamberts | 3.426 | candela/m2 | cd/m2 | candela/m2 | 0.2919 | foot-Lamberts | fl |
| FORCE and PRESSURE or STRESS | FORCE and PRESSURE or STRESS | |||||||
| lbg | poundforce | 4.45 | newtons | N | newtons | 0.225 | poundforce | lbf |
| psi | poundforce per square inch | 6.89 | kilopascals | kPa | kilopascals | 0.145 | poundforce per square inch | psi |
*SI is the symbol for the International System of Units. Approximate rounding should be made to comply with Section 4 of ASTM E380.
Use of SI units is encouraged with Part VI. Future editions of Part VI will use only SI units. The conversions will be based primarily on AASHTO guides. Specific conversion of standards will be subjected to the FEDERAL REGISTER rulemaking process.