Converting Customary Units

In the US customary system, we measure length, weight, and capacity using specific units. To convert between these units, you just need to know the basic conversion factors and one simple rule:

• Larger unit to a smaller unit: Multiply.
• Smaller unit to a larger unit: Divide.

Length

Length measures how long or tall something is.

• $1 \text{ foot (ft)} = 12 \text{ inches (in)}$
• $1 \text{ yard (yd)} = 3 \text{ feet} = 36 \text{ inches}$
• $1 \text{ mile (mi)} = 5,280 \text{ feet}$

Weight

Weight measures how heavy an object is.

• $1 \text{ pound (lb)} = 16 \text{ ounces (oz)}$
• $1 \text{ ton (T)} = 2,000 \text{ pounds}$

Capacity

Capacity (or volume) measures how much liquid a container can hold.

• $1 \text{ cup (c)} = 8 \text{ fluid ounces (fl oz)}$
• $1 \text{ pint (pt)} = 2 \text{ cups}$
• $1 \text{ quart (qt)} = 2 \text{ pints} = 4 \text{ cups}$
• $1 \text{ gallon (gal)} = 4 \text{ quarts}$

Example Problems

Example 1: How many inches are in 4 feet 3 inches? First, convert the feet into inches. Since $1 \text{ foot} = 12 \text{ inches}$, multiply the number of feet by 12: $4 \times 12 = 48 \text{ inches}$ Next, add the extra 3 inches: $48 + 3 = 51 \text{ inches}$

Example 2: Convert 5 quarts to cups. We know that $1 \text{ quart} = 4 \text{ cups}$. Since we are converting from a larger unit (quarts) to a smaller unit (cups), we multiply: $5 \times 4 = 20 \text{ cups}$

Example 3: A box weighs 3 pounds 8 ounces. How many ounces is that? First, convert the pounds to ounces. Since $1 \text{ pound} = 16 \text{ ounces}$, multiply by 16: $3 \times 16 = 48 \text{ ounces}$ Then, add the remaining 8 ounces: $48 + 8 = 56 \text{ ounces}$