How Many Milliliters Are in a Teaspoon?

How many ml are in 1 US teaspoon?

1 US teaspoon equals 4.9289 milliliters, almost always rounded to 5 ml for kitchen use. The math: a US teaspoon is 1/3 of a US tablespoon, and a US tablespoon is 14.79 ml, so a teaspoon is 4.93 ml. For cooking, treating a teaspoon as 5 ml gives accuracy within 1.5 percent. The 5 ml figure is the standard listed on virtually all kitchen measuring spoon sets worldwide. Medical dosing also uses 5 ml as the standard teaspoon equivalent, which is why over-the-counter liquid medications and oral syringes are calibrated to 5 ml marks. The clean 5 ml number is convenient: 1 tsp is 5 ml, 1 tbsp is 15 ml (3 tsp), and 1 fl oz is 30 ml (6 tsp). This makes metric-to-teaspoon conversion easy to memorize.

How does the US teaspoon compare to UK and metric teaspoons?

Unlike tablespoons, which vary significantly between systems, teaspoons are relatively consistent. The US teaspoon is 4.93 ml. The UK teaspoon is 5.92 ml, about 20 percent larger. The metric teaspoon used in Australia is exactly 5 ml. For most cooking, the small difference between US and metric teaspoons (just 0.07 ml) is invisible. The UK teaspoon difference matters more for baking, where leavening or spice amounts are measured in single teaspoons; a UK teaspoon of yeast is 20 percent more than a US teaspoon. Most modern UK recipes have shifted to gram measurements anyway, which sidesteps the teaspoon-size question. For Australian recipes using metric measurements, 5 ml is the standard, matching most measuring spoon sets sold globally.

How do common teaspoon amounts convert to ml?

For US teaspoons (rounded to 5 ml each): 1/4 tsp is 1.25 ml, 1/2 tsp is 2.5 ml, 1 tsp is 5 ml, 2 tsp is 10 ml, 3 tsp is 15 ml (1 tablespoon), 4 tsp is 20 ml, and 6 tsp is 30 ml (1 fluid ounce). The clean 5 ml round number makes the math easy: any teaspoon amount converts to ml by multiplying by 5. For amounts smaller than 1/4 teaspoon (1.25 ml), the volume gets impractical to measure with standard spoons; a graduated medicine syringe or precision scale gives better accuracy. The standard 'pinch' (1/8 teaspoon) equals about 0.6 ml, which is too small to measure reliably with standard kitchen tools.

When does the teaspoon-to-ml conversion matter most?

Medicine dosing is the most precision-critical case. Liquid medications for adults and children are dosed in milliliters, with teaspoon equivalents listed for older instructions. A 5 ml medicine syringe is more accurate than a kitchen teaspoon, since household teaspoons can hold 6-7 ml when not calibrated. International recipes are another situation: European and Asian recipes often list small liquid amounts in milliliters, and the 5 ml conversion makes the math fast. Cocktail and bartending recipes use 5 ml 'bar spoons' for precise stirring and small pours. For most home cooking, the teaspoon-to-ml conversion appears less often than tablespoon or cup conversions, but the 5 ml round number is worth memorizing as the foundation of all metric kitchen math.