Tea Caffeine Calculator

The easiest to use caffeine calculator available. Look up caffeine in green tea, oolong tea, black tea, and now Starbucks Teas. 

The Tea Caffeine Calculator: loose leaf teas as well as caffeine in Starbucks tea. Use this for quick lookup of how much caffeine you are drinking right now. 

The Advanced Tea Caffeine Calculator: for loose leaf tea lovers, allows you to select tea, size, and number of steeps. Use this if you multi-steep loose leaf tea. 

Ounce to Milliliter Serving Conversion
Ounce Size 8oz 12oz 16oz 20oz
Milliliter Size 237ml 355ml 473ml 591ml
Starbucks Size Short Tall Grande Venti


Caffeine varies with water temperature, tea type, steep time, roast, growing conditions, and extraction method.

Teas brewed at ratio of 1:50 (grams/ml) boiling water to tea leaves, steeped for 6 minutes. Cold brew, 4 hours.