How Many Teaspoons in a Cup?

Multiply the cups by 48. The number is two steps rolled into one: 16 tablespoons per cup, times 3 teaspoons per tablespoon.

Teaspoons suit small cup amounts. 1/8 cup is 1/8 × 48 = 6 teaspoons, and 2/3 cup works out to 32 teaspoons.

Large results are easier to measure in tablespoons. Divide the teaspoon count by 3 and keep any remainder as teaspoons, so 32 teaspoons become 10 tablespoons plus 2 teaspoons. To go back from teaspoons, divide by the same number; see teaspoons to cups.

The teaspoon is almost the same size everywhere: 4.93 ml in the US and 5 ml in the UK, Australia, Canada and New Zealand. Filling a US cup with metric teaspoons takes about 47.3 spoonfuls rather than 48.

The cup is where the gap grows. A metric cup of 250 ml holds 50.72 teaspoons of the US kind, so a British or Australian cup is a little more generous than an American one.

For home cooking, the NIST metric kitchen chart pairs 1 teaspoon with 5 ml and 1 cup with 240 ml. At that rounding, the count of teaspoons per cup does not change.

Teaspoons are handy for splitting a batch into small doses. A jar holding 1 1/4 cups of homemade spice rub contains 60 teaspoons; at 2 teaspoons per use, it covers thirty meals.

The same math shrinks a recipe for a test batch. Cut a dressing that uses 1/2 cup of oil and 1/4 cup of vinegar to one twelfth, and you need only 2 teaspoons of oil and 1 teaspoon of vinegar.