How much caffeine is in iced coffee?

An 8 fl oz cup of iced coffee has 74 mg of caffeine.

That's about three quarters of a cup of brewed coffee, and 19% 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 26 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 iced coffee by about 7:40 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	12:40 pm	5:40 pm	Any time
10 pm	1:40 pm	6:40 pm	Any time
11 pm	2:40 pm	7:40 pm	Any time
Midnight	3:40 pm	8:40 pm	Any time
1 am	4:40 pm	9:40 pm	Any time

For an 8 fl oz cup of iced 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 iced coffee peaks in your blood about 75 minutes after you start it, at roughly 63 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	52 mg	34 mg	23 mg	15 mg

So one had at 3 pm leaves about 26 mg at 11 pm. How long caffeine lasts explains the curve.

How it compares

Iced coffee is stronger than 29% of the 22 coffees made at home we track, by caffeine per serving.

Per fluid ounce (9.3 mg) it is stronger than 28% of them.

To reach 400 mg in a day you would need about 5½ of these.

Less caffeine

Espresso 63 mg, Single shot
Instant Coffee 62 mg, 8 fl oz cup
illy Espresso 60 mg, 1 shot

More caffeine

Nespresso Original Espresso 50 to 100 mg, 1 espresso
Nespresso Vertuo Espresso 50 to 100 mg, 1 espresso
Nescafé Espresso Concentrate 80 mg, 2 tbsp, black

FAQ

Is iced coffee high in caffeine?

It is moderate. An 8 fl oz cup of iced coffee has 74 mg, which is 78% of the 95 mg in an 8 fl oz cup of brewed coffee.

Can I drink iced coffee at night?

Earlier is better. Had at 7 pm, it leaves about 45 mg in an average adult at an 11 pm bedtime. The latest time for an 11 pm bedtime is about 7:40 pm.

How long does the caffeine in iced coffee last?

It peaks about 75 minutes after you start it. Of the 74 mg, about 34 mg is still in you 6 hours later and 15 mg after 12 hours, for an average adult with a 5-hour half-life.

Does iced coffee have more caffeine than Red Bull?

No. An 8 fl oz cup of iced coffee has 74 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.