How to convert household measures: teaspoons to gallons, ounces to pounds, inches to yards
HESI A2 topic: Household and metric measures
- 1 tbsp = 3 tsp, and 1 fl oz = 2 tbsp.
- 1 cup = 8 fl oz, and 1 pint = 2 cups.
- 1 quart = 2 pints, and 1 gallon = 4 quarts.
- Pound = 16 oz; foot = 12 in; yard = 3 ft.
- Multiply to reach a smaller unit; divide to reach a bigger one.
Key facts
- Volume chain: 1 tbsp = 3 tsp, 1 fl oz = 2 tbsp, 1 cup = 8 fl oz, 1 pint = 2 cups, 1 quart = 2 pints, 1 gallon = 4 quarts.
- Useful totals: 1 cup = 16 tbsp, 1 quart = 32 fl oz, 1 gallon = 128 fl oz = 16 cups.
- Weight: 1 lb = 16 oz. Length: 1 ft = 12 in, 1 yd = 3 ft = 36 in.
Show all 6 key factsShow fewer
- Going to a smaller unit, multiply (the number gets bigger); going to a bigger unit, divide (the number gets smaller).
- Mixed units: 2 lb 5 oz = 2 × 16 + 5 = 37 oz; going back, divide by 16 and keep the remainder as ounces.
- Rounded metric bridges used in health-care math: 1 tsp ≈ 5 mL, 1 tbsp ≈ 15 mL, 1 fl oz ≈ 30 mL, 1 kg ≈ 2.2 lb.
Quick check1 question · 2 more at the end
A soup recipe calls for 3 quarts of broth. How many cups of broth is this?
Correct answer: B.
A quart is 2 pints and a pint is 2 cups, so 1 quart = 4 cups. Going from a bigger unit to a smaller one, multiply: 3 × 4 = 12 cups. A sense check helps: cups are smaller than quarts, so the number must get bigger.
A This uses 2 cups per quart, mixing up a quart with a pint (1 pint = 2 cups, but 1 quart = 2 pints = 4 cups).
B Correct: 1 quart = 2 pints = 4 cups, so 3 quarts = 3 × 4 = 12 cups.
C This uses 8 cups per quart, confusing the 8 fluid ounces in a cup with the number of cups in a quart.
D This divides by 4 instead of multiplying; converting to a smaller unit must give a bigger number.
Full lesson
Each part starts with its main idea. Open a part when you want the details.
The short answer: Household volume units form a chain: 3 tsp = 1 tbsp, 2 tbsp = 1 fl oz, 8 fl oz = 1 cup, 2 cups = 1 pint, 2 pints = 1 quart, 4 quarts = 1 gallon. Also 16 oz = 1 lb, 12 in = 1 ft and 3 ft = 1 yd. Multiply to reach a smaller unit; divide to reach a bigger one.
1 How do the household volume units link together?Every household volume unit is a small whole number of the unit just below it, so you can climb the chain one step at a time. 1 min
Every household volume unit is a small whole number of the unit just below it, so you can climb the chain one step at a time. Elsevier's description of HESI A2 Math, as schools publish it, lists household measures, and these are the factors NIST publishes.
| Unit | Equals | Running total |
|---|---|---|
| 1 tablespoon (tbsp) | 3 teaspoons (tsp) | 3 tsp |
| 1 fluid ounce (fl oz) | 2 tbsp | 6 tsp |
| 1 cup | 8 fl oz | 16 tbsp |
| 1 pint (pt) | 2 cups | 16 fl oz |
| 1 quart (qt) | 2 pints | 32 fl oz |
| 1 gallon (gal) | 4 quarts | 128 fl oz |
Read the table from the top down and each row only uses the row above it. That is all you need for any volume problem.
2 How do I convert across several steps?Multiply one link at a time and keep the units written on every number. 1 min
Multiply one link at a time and keep the units written on every number. Going down to a smaller unit always gives a bigger number.
Worked example 1. How many teaspoons are in 1 cup?
- Cups to fluid ounces: 1 × 8 = 8 fl oz.
- Fluid ounces to tablespoons: 8 × 2 = 16 tbsp.
- Tablespoons to teaspoons: 16 × 3 = 48 tsp.
Worked example 2. A jug holds 40 fl oz. How many cups is that?
- Going up to a bigger unit, so divide: 40 ÷ 8 = 5 cups.
- Sense check: cups are bigger than fluid ounces, so the number got smaller.
Classic wrong turn: using 16 fl oz per cup. Sixteen ounces is a pound of weight, and 16 fl oz is a pint.
3 How do pounds, ounces, feet and yards work?Weight and length use the same multiply-or-divide habit, with 16 ounces in a pound, 12 inches in a foot and 3 feet in a yard. 1 min
Weight and length use the same multiply-or-divide habit, with 16 ounces in a pound, 12 inches in a foot and 3 feet in a yard.
Worked example 3. A package of rice weighs 2 lb 5 oz. Write this in ounces.
- Pounds to ounces: 2 × 16 = 32 oz.
- Add the leftover ounces: 32 + 5 = 37 oz.
To go back, divide by 16 and keep the remainder: 37 ÷ 16 = 2 remainder 5, so 2 lb 5 oz.
Worked example 4. Add 1 lb 10 oz and 14 oz.
- Add like units: 1 lb and 10 + 14 = 24 oz, so 1 lb 24 oz.
- Regroup: 24 oz = 1 lb 8 oz.
- Total: 2 lb 8 oz.
Length works the same way: 5 ft 8 in = 5 × 12 + 8 = 68 in, and 2 yd = 6 ft = 72 in.
Classic wrong turn: treating ounces like decimals. 2 lb 5 oz is not 2.5 lb; it is 2 and 5/16 lb, about 2.31 lb.
4 What about going to metric?Health-care math usually bridges to metric with a few rounded values, and the question will tell you which one to use. 1 min
Health-care math usually bridges to metric with a few rounded values, and the question will tell you which one to use. Common ones are 1 tsp ≈ 5 mL, 1 tbsp ≈ 15 mL, 1 fl oz ≈ 30 mL and 1 kg ≈ 2.2 lb.
NIST lists the more precise values (a teaspoon is about 4.93 mL, a fluid ounce about 29.57 mL), so always use the factor given in the stem. For the metric ladder and step-by-step metric conversions, see our lesson on unit conversions.
Common mistakes
The traps students fall into most. Read these before you practice.
Watch out: A fluid ounce measures volume and an ounce measures weight: 8 fl oz is a cup, 16 oz is a pound.
Watch out: A tablespoon is 3 teaspoons, not 2; a fluid ounce is 2 tablespoons.
Watch out: A quart is 2 pints (4 cups), not 2 cups.
Watch out: 5 lb 4 oz is 5.25 lb, not 5.4 lb; an ounce is one-sixteenth of a pound, not one-tenth.
Watch out: Regroup leftover small units: 1 lb 22 oz should be written as 2 lb 6 oz.
How to remember it
Say the volume chain out loud in one breath as "3, 2, 8, 2, 2, 4" for teaspoon, tablespoon, fluid ounce, cup, pint, quart, gallon.
Memory hook: "Three spoons make a big spoon, two big spoons make an ounce, eight ounces make a cup, then 2, 2, 4 to the gallon."
Self-check:
- How many tablespoons are in 2 cups?
- Write 50 oz in pounds and ounces.
- How many inches are in 2 yd 1 ft?
Show answers
- 32 tbsp.
- Cups to fluid ounces: 2 × 8 = 16 fl oz.
- Fluid ounces to tablespoons: 16 × 2 = 32 tbsp.
- Check: 1 cup = 16 tbsp, so 2 cups = 32 tbsp.
- 3 lb 2 oz.
- Going up to a bigger unit, so divide: 50 ÷ 16 = 3 remainder 2.
- The 3 is pounds and the remainder 2 is ounces.
- Check: 3 × 16 + 2 = 48 + 2 = 50 oz.
- 84 in.
- Yards to feet: 2 × 3 = 6 ft.
- Add the extra foot: 6 + 1 = 7 ft.
- Feet to inches: 7 × 12 = 84 in.