# Units of Measure

In , there are two systems of commonly used measurements: Metric and US Customary. We need both because the US won’t adopt the metric system completely.

## The Metric and US Customary System

These are commonly used prefixes for the Metric System:

Table 1.6 Common Prefixes for the Metric System
Prefix Amount
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

Table 1.7 Common Mass Units for Metric and US Customary Systems
Metric System US Customary System Conversions
Microgram (μg) Ounce (oz) 1 oz = 28.35 g
Milligram (mg) Pound (lb) 1 lb = 453592 mg
Gram (g) Pound (lb) 1 lb = 454 g
Kilogram (kg) Pound (lb) 2.2 lbs = 1 kg

### Volume

Table 1.8 Common Volume Units for Metric and US Customary Systems
Metric System US 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

Table 1.9 Common Length Units for Metric and US Customary Systems
Metric System US 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

### Learning Activities

Technology Note: The second edition of the Human Nutrition Open Educational Resource (OER) textbook features interactive learning activities.  These activities are available in the web-based textbook and not available in the downloadable versions (EPUB, Digital PDF, Print_PDF, or Open Document).

Learning activities may be used across various mobile devices, however, for the best user experience it is strongly recommended that users complete these activities using a desktop or laptop computer.