Energy / Explainer
How Much Coffee Is Too Much? The Honest Numbers
9 July 2026
Somewhere between "coffee is poison" and drinking it straight from the pot sits an actual number, and it's friendlier than the wellness industry suggests.
The number
The guideline used by UK and European food safety bodies is up to 400mg of caffeine a day for healthy adults — roughly four mugs of instant, three flat whites, or two strong filter coffees, depending on how honestly you pour. Pregnant women are advised to stay under 200mg. Below those levels, moderate coffee drinking keeps showing up in large studies looking either neutral or mildly positive for long-term health.
Why the total isn't the whole story
400mg spread badly feels worse than 300mg spread well. Caffeine's half-life is five to six hours: a 4pm coffee still has half its caffeine in your system at 9pm, quietly shaving depth off your sleep — which makes tomorrow more tired, which makes tomorrow need more coffee. That loop, not the daily total, is where most "coffee problems" actually live. We've mapped it in the crash explainer.
Signs you're past your personal limit
- Jitters, racing heart, or a tense jaw by mid-morning
- Needing coffee to feel normal rather than to feel good
- Afternoon slumps that only another coffee fixes
- Taking 30+ minutes to fall asleep despite being tired
- Headaches on days you skip it entirely
Individual tolerance varies enormously — some people metabolise caffeine twice as fast as others, which is why your colleague's espresso-at-9pm party trick proves nothing about you.
If you're cutting back
Don't quit cold — the withdrawal headache is real and unnecessary. Drop one cup at a time over a week or two, move your last coffee earlier before you shrink the total, and keep the ritual with decaf or a functional alternative if the mug itself is half the point. For most people the goal isn't zero. It's coffee that works for you again, on a schedule your sleep can live with.
This article is general information, not medical advice. If symptoms are severe, persistent, or worrying you, speak to your GP or a pharmacist.