Convert Tablespoon to Teaspoon

One US tablespoon equals exactly 3 US teaspoons — a fixed ratio built into the definition of both units. The tablespoon is 1/16 of a US cup (14.7868 mL) and the teaspoon is 1/48 of a US cup (4.9289 mL). Multiplying tablespoons by 3 gives teaspoons; dividing teaspoons by 3 gives tablespoons. A 2-tablespoon measure of olive oil is 6 teaspoons (29.57 mL); ¾ tablespoon of vanilla extract is 2¼ teaspoons.

Baking is where this ratio earns its keep. Leavening agents — baking powder, baking soda, yeast — are almost always specified in teaspoons because the quantities are small and precision matters. A recipe calling for 1 tablespoon of baking powder can be split as 3 teaspoons without any arithmetic beyond the factor of 3; scaling to half a recipe yields 1½ teaspoons.

The ratio is consistent across US customary tablespoons and teaspoons, but it does not hold for the Imperial (UK/Australian) versions, which have slightly different absolute volumes. An Australian tablespoon is 20 mL (4 metric teaspoons of 5 mL each), while a US tablespoon is about 14.79 mL (3 teaspoons). An Australian recipe specifying '1 tablespoon' of spice means noticeably more than a US tablespoon — closer to 1⅓ US tablespoons. That gap can shift the balance of a spice blend or the structural integrity of a baked good.

Liquid medicines are another context. Over-the-counter dosing instructions sometimes specify in teaspoons (5 mL) or tablespoons (15 mL). Because the medical community increasingly moves to milliliters to reduce dosing errors, knowing that 1 tablespoon = 3 teaspoons = 15 mL links both systems without ambiguity.