1.2.7. Units of Measure

The Metric and U.S. Customary Systems

In nutrition, there are two systems of commonly used measurements: metric and U.S. customary. We need both because the U.S. won’t adopt the metric system completely.

These are commonly used prefixes for the metric system:

Micro- (μ) 1/1,000,000th (one millionth)
Milli- (m) 1/1000th (one thousandth)
Centi- (c) 1/100th (one hundredth)
Deci- (d) 1/10th (one tenth)
Kilo- (k) 1000x (one thousand times)

Mass

Metric system U.S. customary system Conversions
Microgram (μg) Ounce (oz) 1 oz = 28.35 g
Milligram (mg) Pound (lb) 1 lb = 16 oz
Gram (g) 1 lb = 454 g
Kilogram (kg) 1 kg = 2.2 lbs

Volume

Metric system U.S. customary system Conversions
Milliliter (mL) Teaspoon (tsp) 1 tsp = 5 mL
Deciliter (dL) Tablespoon (tbsp) 1 tbsp = 3 tsp = 15 mL
Liter (L) Fluid ounce (fl oz) 1 fl oz = 2 tbsp = 30 mL
Cup (c) 1 c = 8 fl oz = 237 mL
Pint (pt) 1 pt = 2 c = 16 fl oz
Quart (qt) 1 qt = 4 c = 32 fl oz = 0.95 L
Gallon (gal) = 4 qt 1 gal = 4 qt

Length

Metric system U.S. customary system Conversions
Millimeter (mm) Inch (in) 1 in = 25.4 mm
Centimeter (cm) Foot (ft) 1 ft= 30.5 cm
Meter (m) Yard (yd) 1 yd = 0.9 m
Kilometer (km) Mile (mi) 1 mi = 1.6 km

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Fundamentals of Health and Physical Activity by Kerri Z. Delaney and Leslie Barker is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.