Daily Caffeine Intake Calculator
Add drinks to the list on the left; today's total and your limit status update instantly on the right, with the decay curve and list below.
Input
Pick a drink to preview its caffeine.
No drinks added yet.
Result
- Recommended limit
- —
- Remaining
- —
- Left after 5h
- —
- Left after 10h
- —
Remaining caffeine over time (≈5h half-life)
Today's drinks
| Drink | Qty | Caffeine | Remove |
|---|
The dashed line is your limit; the curve is what remains of the current total over time. The 5-hour half-life is an average — individual range is roughly 2–8 hours.
Contents are estimates from published brand values and common references; recipes and batches vary. If pregnant, on medication, or managing a condition, consult a clinician.
ready to use.
- Visible firstKeep the input and result positions clear.
- Results firstPut the main number up front and keep the process secondary.
- Less to askNo sign-up or extra information before using the tool.
Keeping today's caffeine inside a sensible limit
This calculator totals the drinks you log and compares them with a limit that fits your age and weight: 400 mg a day for healthy adults, 300 mg for pregnancy and seniors, and 2.5 mg per kilogram for children and teens.
Content data comes from published brand values and common references. The same menu item varies by shots, batch, and season — read conservatively when you are near the limit.
Where the limits come from
They follow widely used public-health conventions.
- Adults: 400 mg/day, a level generally not associated with clear harm
- Pregnancy: 300 mg here; some bodies advise 200 mg or less, so stricter is fine
- Children and teens: 2.5 mg per kg of body weight
- Seniors and heart conditions: common practice is lower
Screen flow: log, total, curve
Choose category → brand → drink, add it with a quantity, and the total, limit, and remainder update instantly. The list is stored in this browser for today only and clears when the date changes.
Reading the half-life curve
Caffeine's blood half-life averages around five hours.
- A simple exponential decay: about 50% left after 5h, 25% after 10h
- Individual range is wide, roughly 2–8 hours (pregnancy, oral contraceptives, liver function, smoking)
- Intake even six hours before bed has been reported to affect sleep
Example: a Pike Place Tall plus a can of cola
The sample button adds this pair.
- Total
- 235 + 34 = 269 mg
- Vs. adult limit
- 269 ÷ 400 = 67%
- After 5h
- ≈ 135 mg
- After 10h
- ≈ 67 mg
Log the hidden caffeine too
Coffee is not the only source.
- Energy drinks 60–160 mg
- Colas 30–50 mg, black tea 40–70 mg, green tea 20–40 mg
- Chocolate and some pain relievers contain smaller amounts
- Even decaf keeps about 2–15 mg per cup
Signs you may have overdone it
Sensitivity differs, but common signals include:
- Palpitations, shaky hands, anxiety
- Acid reflux or stomach upset
- Trouble falling asleep, lighter sleep
- If it recurs, move intake earlier and cut the total first
Limits of the data
Contents are not fixed values. Roasts, shot counts, and seasonal recipes shift them, and bottled drinks change with reformulations. This tool is a planning estimate, not medical advice.
Caffeine intake FAQ
What is the recommended daily caffeine limit?
For healthy adults, 400 mg a day is the widely used benchmark. Pregnancy uses 300 mg here (some bodies advise 200 mg or less), children and teens 2.5 mg per kg, and seniors or people with heart conditions commonly aim lower.
How is the decay curve computed?
It assumes simple exponential decay with an average five-hour half-life: about 50% remains after 5 hours and 25% after 10. Real half-lives vary from roughly 2 to 8 hours between individuals.
Where is my list stored?
In this browser's localStorage, keyed to today's date. Nothing is sent to a server; the list clears when the date changes and does not sync across devices.
How accurate are the content values?
They are estimates from published brand values and common references. Shots, sizes, and reformulations change them, so interpret conservatively near your limit.
Is a headache normal when I quit coffee?
Regular caffeine users who stop abruptly often get withdrawal headaches and fatigue for a few days. Tapering gradually is the usual advice; see a clinician if symptoms are severe.
Reviewed: 2026-07-11. Limits follow common public-health conventions and can differ with personal conditions.