Daily Caffeine Calculator
Add up the caffeine in your day's coffee, tea and energy drinks and see it against the 400 mg adult (or 200 mg pregnancy) limit.
Calculator
You're under the limit
221 mg221 mg is 55% of your 400 mg limit — about 179 mg of headroom, roughly 2 more espresso.
Serving sizes used
- 2× Espresso1 oz / 30 mL shot · 126 mg
- 1× Brewed coffee8 oz / 240 mL · 95 mg
Worried about sleep?
This tool totals the day. To see how long caffeine stays in your system, use the caffeine half-life calculator.
About this calculator
Caffeine sneaks in from more than just coffee — tea, cola and energy drinks all add up. This calculator totals the caffeine across everything you've had today and puts it against the limits health bodies use: about 400 mg a day for healthy adults (FDA, Mayo Clinic) and under 200 mg a day in pregnancy (ACOG). Add each drink, set how many, and see your total, what share of the limit it is, and roughly how many more you could have.
How to read your results
The hero number is your day's caffeine in milligrams. "% of daily limit" compares it to your chosen ceiling — 400 mg for adults, 200 mg if you tick the pregnant/sensitive option. "Room left" estimates how many more of your first drink fit under the limit. The mug fills as you approach the limit and turns red once you go over. We flag "close to the limit" from 80% upward.
How it's calculated
Each drink uses a representative caffeine figure per standard serving: espresso 63 mg (1 oz shot), brewed coffee 95 mg (8 oz), instant 62 mg, decaf 2 mg (never zero), cold brew 200 mg (16 oz, the most variable), black tea 47 mg, green tea 28 mg, cola 35 mg (12 oz), and an energy drink 80 mg. Total = the sum of each figure × its count. Percent of limit = total ÷ limit × 100. Room left = (limit − total) ÷ the caffeine in your first drink.
Worked example
Two espressos and one brewed coffee, against the 400 mg adult limit.
2 × 63 mg + 95 mg = 221 mg — about 55% of the 400 mg limit, leaving ~179 mg of headroom (roughly 2 more espressos).
Frequently asked questions
How much caffeine is too much?
For most healthy adults the FDA and Mayo Clinic put about 400 mg a day — roughly four 8 oz cups of brewed coffee — as the amount not generally linked to negative effects. In pregnancy, ACOG advises staying under 200 mg a day. These are general thresholds, not personal medical advice.
Is decaf really caffeine-free?
No. An 8 oz cup of decaf still has around 2 mg of caffeine (sometimes more), so it is low but never truly zero. That is why this tool counts decaf at 2 mg rather than skipping it.
Why is cold brew so high?
A 16 oz ready-to-drink cold brew often lands near 200 mg, and concentrates can be far stronger. Cold brew is the most variable drink here — brand, ratio and dilution swing it widely — so treat its figure as a starting point and check the label.
Does this tell me when the caffeine wears off?
No — this adds up the day's dose. To see how long caffeine lingers in your system (it has a half-life of several hours, which is why a late coffee disturbs sleep), use the caffeine half-life calculator instead.
Are the numbers exact?
They are representative midpoints. Real drinks vary by brand, bean, brew strength and serving size, so use the total as a guide rather than a precise measurement.
Sources
- www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much
- www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/caffeine/art-20049372
- www.acog.org/womens-health/experts-and-stories/ask-acog/how-much-coffee-can-i-drink-while-pregnant
Reviewed by the YouCalc Team · Last reviewed
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