Teaspoon (tsp) to Milliliter (ml)
In the US, 1 teaspoon equals 4.929 ml — slightly less than the 5 ml metric teaspoon used in the UK and most of Europe. For everyday American cooking, the difference is rarely significant, but it can matter in pharmaceutical contexts or when following metric recipes precisely.
Frequently asked questions
In the US, 1 teaspoon equals 4.929 ml. For practical cooking purposes, many people round this to 5 ml. The UK metric teaspoon is defined as exactly 5 ml.
Three US teaspoons equal 3 × 4.929 ml = 14.787 ml, which is exactly 1 US tablespoon. In metric, 3 teaspoons at 5 ml each gives 15 ml — one metric tablespoon.
In the US, 1 tablespoon = 3 teaspoons = 14.787 ml. This 3-to-1 ratio is the same as in the UK, even though the individual measures are slightly smaller in US customary units.
Small errors in leavening agents like baking powder or baking soda can significantly affect results. Too much causes a metallic taste or collapse; too little and the baked good won't rise. Always level off the spoon with a straight edge for accuracy.