Formula: tsp to mL
mL = tsp × teaspoon_size_mL
For US teaspoon: mL = tsp × 4.92892
For metric teaspoon: mL = tsp × 5
For UK teaspoon: mL = tsp × 5.91939
Why are there different teaspoons?
Unlike kilograms or meters, “teaspoon” is not globally standardized. Professional recipe sites (Allrecipes, The Spruce Eats) often assume 1 tsp = 5 mL to keep things simple. US nutritional labeling, however, often retains 4.9289 mL. UK historical measures are slightly larger.
Medication & pediatric notes
Many pediatric charts and medical instructions say “1 teaspoon = 5 mL” because it’s a round number and safer to communicate. If you are dosing medicine: always follow your doctor's or pharmacist’s indicated mL, not the household spoon.
FAQ
1. How many mL is 1/2 tsp?
US: ~2.464 mL. Metric/medical: 2.5 mL.
2. How many teaspoons is 10 mL?
Metric: 10 ÷ 5 = 2 tsp. US: 10 ÷ 4.9289 ≈ 2.028 tsp.
3. Can I also convert tbsp here?
Yes: 1 tbsp (US) = 3 tsp. So choose the tsp standard, convert tbsp × 3 first, then to mL.
Full original guide (expanded)
Here you can add regional notes (India/UK/US cooking), kitchen tips, and links to broader cooking-conversion tools to outrank generic converters.