Measurement
Measurement lets us describe the size, weight, and volume of things using numbers and units. Scientists, cooks, builders, and athletes all use measurement every day.
Length
Length measures how long or tall something is.
| US Customary | Metric |
|---|---|
| Inch (in) — about the width of your thumb | Millimeter (mm) |
| Foot (ft) = 12 inches | Centimeter (cm) = 10 mm |
| Yard (yd) = 3 feet | Meter (m) = 100 cm |
| Mile (mi) = 5,280 feet | Kilometer (km) = 1,000 m |
Choose the right unit: use inches for a pencil, feet for a room, miles for a road trip.
Weight and Mass
Weight tells us how heavy something is.
| US Customary | Metric |
|---|---|
| Ounce (oz) | Gram (g) |
| Pound (lb) = 16 oz | Kilogram (kg) = 1,000 g |
| Ton = 2,000 lb | Metric ton = 1,000 kg |
Quick Reference
A dollar bill weighs about 1 gram. A pineapple weighs about 1 kilogram. A small car weighs about 1 metric ton.
Capacity (Volume)
Capacity measures how much liquid a container holds.
| US Customary | Metric |
|---|---|
| Teaspoon (tsp) | Milliliter (mL) |
| Cup (c) = 8 fl oz | Liter (L) = 1,000 mL |
| Pint (pt) = 2 cups | |
| Quart (qt) = 2 pints | |
| Gallon (gal) = 4 quarts |
Memory Tool: Gallon House
1 Gallon = 4 Quarts = 8 Pints = 16 Cups
Converting Units
To convert to a smaller unit, multiply. To convert to a larger unit, divide.
Examples
3 feet to inches: 3 × 12 = 36 inches
48 inches to feet: 48 ÷ 12 = 4 feet
2.5 kg to grams: 2.5 × 1000 = 2,500 g
Quick Quiz
Test what you just learned. Choose the best answer for each question.