Customary units of measurement
US customary units measure length (inches, feet, yards, miles), weight (ounces, pounds, tons) and capacity (cups, pints, quarts, gallons). To convert, multiply to go to a smaller unit and divide to go to a bigger one. This page has the conversion tables, the Gallon Man memory trick, a converter, and worked examples.
Customary conversion tables
| Length | 12 in = 1 ft · 3 ft = 1 yd · 36 in = 1 yd · 5,280 ft = 1 mi |
| Weight | 16 oz = 1 lb · 2,000 lb = 1 ton |
| Capacity | 8 fl oz = 1 cup · 2 cups = 1 pt · 2 pt = 1 qt · 4 qt = 1 gal |
The Gallon Man trick
Draw a big G (gallon). Inside it, 4 Qs (quarts). Inside each Q, 2 Ps (pints). Inside each P, 2 Cs (cups). Count them: 1 gallon = 4 quarts = 8 pints = 16 cups.
Unit converter
Choose length, weight or capacity. It says whether to multiply or divide.
Worked examples
5 feet to inches
Smaller unit, so multiply: 5 × 12 = 60 in.
48 ounces to pounds
Bigger unit, so divide: 48 ÷ 16 = 3 lb.
3 gallons to cups
3 × 16 = 48 cups.
65 inches in feet and inches
65 ÷ 12 = 5 r 5: 5 ft 5 in.
Common mistakes
How to teach it at home
Bake together
Recipes use cups, tablespoons and ounces.
Measure heights
Record family heights in feet and inches.
Read labels
Milk in gallons and quarts, flour in pounds.
By grade
- Grade 4 (4.MD.A.1): convert larger units to smaller ones within a system.
- Grade 5 (5.MD.A.1): convert in both directions and solve multi-step problems.
- See also metric units.
Worksheets and practice
Customary units worksheet: printable PDF with an answer key. · Make a fresh test
Last reviewed
Questions parents ask
How many inches are in a foot?
12.
How many cups are in a gallon?
16. There are 2 cups in a pint, 2 pints in a quart and 4 quarts in a gallon.
How many ounces are in a pound?
16.
How do you convert customary units?
Multiply to go to a smaller unit and divide to go to a bigger one.
How many feet are in a mile?
5,280.