Caffeine Intake Calculator
A day's caffeine from coffees, teas, energy drinks and colas — at the caffeine each typically carries, which you can adjust — against the usual adult limit, with the amount per kilogram of body weight and how many more of your main drink the limit allows.
Caffeine adds up across drinks that carry very different amounts: a brewed coffee 95 mg or more, an espresso 63, a black tea 47, an energy drink 80 per can, a cola 34.
How the caffeine intake calculator works
Caffeine adds up across drinks that carry very different amounts: a brewed coffee 95 mg or more, an espresso 63, a black tea 47, an energy drink 80 per can, a cola 34. The commonly cited adult limit is 400 mg a day, or about 3 mg per kilogram for smaller people; pregnancy guidance is 200. Totalling the day and comparing with the limit is the whole sum — the per-drink figures are inputs because a large café latte can hold twice the default.
Formula: total = Σ drinks × mg each; share of limit = total / limit; per kg = total / weight
Worked examples
| Inputs | Caffeine today (mg) | Note |
|---|---|---|
| Two coffees, a shot, a tea and a cola | 334 | about 330 mg — within the limit |
| A heavy day | 604 | over |
| Pregnancy limit | 334 | the same day is over |
FAQFrequently asked questions
How much caffeine is safe?
Up to about 400 mg a day for most healthy adults, 200 mg in pregnancy, and less for adolescents. Individual tolerance varies a lot, which is why the limit is an input.
How much caffeine is in a coffee?
A 250 mL brewed coffee about 95 mg, an espresso shot 63, an instant coffee 60, a large café latte 150 or more. Tea is 30 to 50, an energy drink 80 to 160 a can, a cola about 34.
Why per kilogram?
Because the effect scales with body size: 3 mg per kilogram is a common way to state the limit, which gives a lighter person a lower ceiling.
Does timing matter?
Yes — caffeine's half-life is about five hours, so an afternoon coffee is still a third present at bedtime. The separate caffeine half-life page covers the timing.
What about decaf?
Two to five milligrams a cup — not zero, but close enough to ignore unless you drink a great deal of it.
Where these figures come from
- US FDA — Safe Minimum Internal Temperatures — the internal temperatures the roasting calculator targets
- NIST SP 811 — Guide for the Use of the International System of Units — the exact weight and volume conversions used throughout
- UK Food Standards Agency — food safety and labelling standards
Last checked: September 2026. Baking ratios follow standard baker's percentage practice; roasting guidance follows published safe internal temperatures.