Everyday Tools
Caffeine Calculator
Total your day’s caffeine across tea, coffee, cola and energy drinks.
✓ Free
✓ No account
◉ Runs on this device
Everyday Tools
Powering up the tool…
TOOL CAFFEINE-CAL
What this tool does
About the caffeine calculator
A dated per-serving table, guideline comparisons, zero moralising.
How to use it
- List drinks as drink × count.
- Read the total and per-drink lines.
- Check the guideline percentages.
- The half-life note explains the 3pm coffee at 11pm.
Useful for
- See where the day’s edge came from.
- Compare against the 400mg adult guideline.
- Plan an afternoon cutoff that respects sleep.
Straight answers
Caffeine Calculator FAQ
Is 400mg a hard limit?
It is the widely-cited healthy-adult guideline (≈4 coffees), not a cliff — sensitivity varies hugely, pregnancy guidance halves it, and your sleep is the honest judge. The tool compares; you decide.
Why does afternoon caffeine wreck sleep?
Half-life ~5–6 hours: a 200mg 3pm coffee leaves ~100mg at 9pm — a third of a cup still arguing with your melatonin at midnight. The mg totals make the arithmetic visible.