How much caffeine per day is safe?

How much caffeine is safe in a day? For most healthy adults, the commonly cited ceiling is about 400 mg per day — roughly four cups of brewed coffee — according to the European Food Safety Authority (EFSA). During pregnancy, the widely cited figure drops to about 200 mg per day. But here’s the part that matters: those are population averages, not a personal target. Your own comfortable limit depends on your body weight, your genetics, the medications you take, and hormonal factors — which is why two people can react very differently to the same three coffees.

Who	Commonly cited daily reference
Healthy adult	~400 mg/day (EFSA, FDA)
Single dose	~200 mg (~3 mg/kg body weight)
Pregnancy	~200 mg/day (EFSA, ACOG)
Adolescents	~3 mg/kg/day (EFSA)

Reference points, not prescriptions. For anything health-related, talk to a qualified professional.

How much caffeine per day is safe for a healthy adult?

In its 2015 review, EFSA concluded that habitual intakes up to 400 mg of caffeine per day do not raise safety concerns for the general healthy adult population, and that single doses up to about 200 mg (around 3 mg per kilo of body weight for a 70 kg adult) are fine. The U.S. FDA points to a similar 400 mg figure.

To picture 400 mg, it helps to know how much caffeine is in each drink: it’s roughly four 8 oz cups of brewed coffee, or a couple of strong energy drinks plus a coffee. Crucially, 400 mg is a no-concern ceiling for the average adult — not a daily goal to aim for. The figure is about avoiding unwanted effects such as disrupted sleep, a racing heart, or feeling on edge in the general population; plenty of people feel best well below it.

Why is your personal limit different from the average?

A single number can’t fit everyone, because how fast you clear caffeine varies widely:

• Genetics — a liver enzyme called CYP1A2 sets your baseline speed; some people are “fast” metabolizers, others “slow” (more on that in fast vs slow metabolizers).
• Body weight — the references are partly per-kilo, so a lighter person reaches the same effect with less.
• Smoking — speeds caffeine clearance, so smokers often process it faster.
• Medications — some slow caffeine down, leaving more in your system for longer.
• Hormones — pregnancy and oral contraception slow clearance; caffeine can linger up to twice as long.
• Habit — regular drinkers build some tolerance to the felt effects.

So “400 mg” is a ceiling for the average adult; your comfortable limit could sit well below it.

What about pregnancy, medication, and extra sensitivity?

This is where the general number stops being enough.

• Pregnancy — EFSA and ACOG cite around 200 mg/day, because caffeine crosses the placenta and is cleared much more slowly as pregnancy progresses (up to two to three times slower by the third trimester). This is a conversation to have with your doctor or midwife — the figure is a reference, not personalized advice.
• Medications or health conditions — some medications and conditions change how you handle caffeine or how much is advisable. If that’s you, check with a healthcare professional.
• Extra sensitivity — some people feel wired after a single small cup. That’s normal variation, not a flaw.

CaffIQ counts milligrams and timing; it does not give medical advice or replace your doctor.

What are the signs you’ve had too much?

Without dramatizing: common signs that you’ve gone past your own comfortable level include feeling jittery or restless, a racing heart, an unsettled stomach, feeling on edge, and finding it harder to fall asleep. If you notice them, it’s usually a gentle nudge to space your drinks out or move your last one earlier — not a reason to panic. Timing matters as much as the total, too: a dose late in the day can still be active at bedtime even when your daily total is modest. Where your line sits is personal.

How do you stay under your limit while keeping your coffee?

You don’t have to choose between your coffee and your limit — you just need to see the numbers:

1. Know the milligrams of what you actually drink (caffeine per drink).
2. Spread it through the day rather than stacking it.
3. Mind the afternoon and evening, where caffeine and sleep collide.
4. Reach for a quality specialty decaf when a late cup would push you over.

Doing that math by hand is tedious. CaffIQ adds up your caffeine in real time against a limit tuned to your body, and shows how late you can still enjoy a cup tonight — so you keep the pleasure and master the number.

CaffIQ provides general estimates, not medical advice. For any health question — especially during pregnancy or while on medication — consult a qualified professional.