How much caffeine is in iced tea?

One medium drink (about 17 fl oz) of iced tea has 99 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 35 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 one medium drink (about 17 fl oz) of iced tea by about 5:35 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	10:35 am	3:35 pm	Any time
10 pm	11:35 am	4:35 pm	Any time
11 pm	12:35 pm	5:35 pm	Any time
Midnight	1:35 pm	6:35 pm	Any time
1 am	2:35 pm	7:35 pm	Any time

For one medium drink (about 17 fl oz) of iced tea, 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 one medium drink (about 17 fl oz) of iced tea peaks in your blood about 75 minutes after you start it, at roughly 84 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	70 mg	46 mg	30 mg	20 mg

So one had at 3 pm leaves about 35 mg at 11 pm. How long caffeine lasts explains the curve.

How it compares

Iced tea is stronger than 97% of the 38 teas we track, by caffeine per serving.

Per fluid ounce (5.9 mg) it is stronger than 84% of them.

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

Less caffeine

Sweet Tea 92 mg, 1 medium drink
Bigelow American Breakfast Tea 60 to 90 mg, 1 cup
Bigelow Peak Energy Plus 75 mg, 1 cup

More caffeine

Gyokuro 160 mg, 100 ml, brewed

FAQ

Is iced tea high in caffeine?

It is moderate. One medium drink (about 17 fl oz) of iced tea has 99 mg, which is about the same as an 8 fl oz cup of brewed coffee (95 mg).

Can I drink iced tea at night?

Not if you want to sleep well. Had at 7 pm, it leaves about 61 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 5:35 pm.

How long does the caffeine in iced tea last?

It peaks about 75 minutes after you start it. Of the 99 mg, about 46 mg is still in you 6 hours later and 20 mg after 12 hours, for an average adult with a 5-hour half-life.

Does iced tea have more caffeine than a cup of coffee?

Yes. One medium drink (about 17 fl oz) of iced tea has 99 mg; an 8 fl oz cup of coffee has 95 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.