How much caffeine is in coffee?

An 8 fl oz cup of coffee has 95 mg of caffeine.

That's about one cup of brewed coffee, and a quarter of the 400 mg a day the FDA cites for most healthy adults.

Source: USDA FoodData Central · checked 10 Nov 2026

When did you have it?

Had at 3 pm, about 33 mg is still in you at an 11 pm bedtime. That should not affect most people’s sleep.

Bedtime

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Latest time to drink it

For an 11 pm bedtime, most people should finish an 8 fl oz cup of coffee by about 5:50 pm. The table works it out for other bedtimes and for how sensitive you are: it is the latest time to start one so that the caffeine left stays under the line all night.

Bedtime	Very sensitive under 25 mg	Average under 50 mg	Not very sensitive under 100 mg
9 pm	10:50 am	3:50 pm	Any time
10 pm	11:50 am	4:50 pm	Any time
11 pm	12:50 pm	5:50 pm	Any time
Midnight	1:50 pm	6:50 pm	Any time
1 am	2:50 pm	7:50 pm	Any time

For an 8 fl oz cup of coffee, average clearance (half-life 5 h), 8 hours of sleep. "Any time" means even one at bedtime stays under the line.

How long it lasts

The caffeine from an 8 fl oz cup of coffee peaks in your blood about 75 minutes after you start it, at roughly 81 mg. Half of it is gone in about 5 hours for an average adult; that ranges from roughly 3 to 7 hours, and longer in pregnancy or with some medicines.

Time after	3 hours	6 hours	9 hours	12 hours
Still in you	67 mg	44 mg	29 mg	19 mg

So one had at 3 pm leaves about 33 mg at 11 pm. How long caffeine lasts explains the curve.

How it compares

Coffee is stronger than 67% of the 22 coffees made at home we track, by caffeine per serving.

Per fluid ounce (12 mg) it is stronger than 56% of them.

To reach 400 mg in a day you would need about 4 of these.

Less caffeine

Cappuccino 86 mg, 8 fl oz cup
Latte 86 mg, 8 fl oz cup
Macchiato 85 mg, 1 espresso cup

More caffeine

Chicory Coffee 96 mg, 8 fl oz cup
Nescafé Instant Coffee 113 mg, 12 fl oz cup
Half-Caff Coffee 120 mg, Small pot

FAQ

Is coffee high in caffeine?

It is moderate. An 8 fl oz cup of coffee has 95 mg, which is about the same as an 8 fl oz cup of brewed coffee (95 mg).

Can I drink coffee at night?

Not if you want to sleep well. Had at 7 pm, it leaves about 58 mg in an average adult at an 11 pm bedtime, above the 50 mg most people sleep fine with. The latest time for an 11 pm bedtime is about 5:50 pm.

How long does the caffeine in coffee last?

It peaks about 75 minutes after you start it. Of the 95 mg, about 44 mg is still in you 6 hours later and 19 mg after 12 hours, for an average adult with a 5-hour half-life.

Is there a decaf or lower-caffeine version of coffee?

Yes. Decaf Coffee has 2 to 15 mg in 8 fl oz cup, 92% less.

Does coffee have more caffeine than Red Bull?

Yes. An 8 fl oz cup of coffee has 95 mg; an 8.4 fl oz can of Red Bull has 80 mg.

Method and limits

The caffeine figure comes from USDA FoodData Central; recipes, brewing and batches vary, so a real serving can differ. The curves use a standard one-compartment model with an average 5-hour half-life and a sleep-friendly line of 50 mg; your own body may clear caffeine faster or slower. How it works has the details.

These are estimates for information, not medical advice.