Caffeine in drinks
How much caffeine is in Iced coffee?
Data checked against the source on 2026-10-03 by Oleksii Y.
One 8 fl oz cup (240 g) of Iced coffee has 74.4 mg of caffeine, according to USDA Agricultural Research Service, FoodData Central (FNDDS).
How Iced coffee compares
- Strength: 31 mg per 100 ml.
- One 8 fl oz cup (240 g) has as much caffeine as about three quarters of a cup of brewed coffee, which has 94.8 mg per 8 fl oz cup.
- Of the 13 other coffee drinks in our coffee chart, 7 have more caffeine per serving and 6 have less.
How much will be left at bedtime?
1 × 8 fl oz cup (240 g) of Iced coffee
Left at 11:00 PM (8 h later), average metabolism
≈ 24 mg
Range 12–37 mg (fast to slow metabolism)
To be at 50 mg or less by bedtime, have 74 mg by 7:25 PM (average) or 5:44 PM (slow metabolism).
What sleep studies found near this dose
- Gardiner et al. 2025 (randomized trial): In 23 healthy young men, 100 mg taken 12, 8 or 4 hours before bed had no significant effect on measured or self-rated sleep.
- Gardiner et al. 2023 (meta-analysis): To avoid losing sleep time, the authors suggest a coffee (107 mg per 250 ml) at least 8.8 hours before bed.
Estimate from a simple model: half-life of 3, 5 or 8 hours, 50 mg bedtime target. How we calculate
Caffeine by size
| Serving | Caffeine |
|---|---|
| 8 fl oz cup (240 g) | 74.4 mg |
| Small (360 g) | 111.6 mg |
How long does Iced coffee stay in your system?
Our model halves caffeine every 5 hours for average metabolism, and every 3 or 8 hours for fast or slow metabolism. From one 8 fl oz cup (240 g) of Iced coffee (74 mg), about 37 mg is still in your body 5 hours later and about 19 mg after 10 hours. If you clear caffeine slowly (an 8-hour half-life), about 31 mg is left after 10 hours.
Estimated caffeine left at 11:00 PM from one 8 fl oz cup (240 g) (74 mg), using a half-life of 5 hours for average metabolism and 3 to 8 hours for the range. How we calculate
| Had at | Left at bedtime (average) | Range |
|---|---|---|
| 8:00 AM (15 h before bed) | ≈ 9 mg | 2–20 mg |
| 12:00 PM (11 h before bed) | ≈ 16 mg | 6–29 mg |
| 3:00 PM (8 h before bed) | ≈ 24 mg | 12–37 mg |
| 6:00 PM (5 h before bed) | ≈ 37 mg | 23–48 mg |
How many fit in a day?
Reference amounts are for caffeine from all sources combined. Counted at the upper end of the stated amount, one serving at a time:
- Up to 400 mg a day for most healthy adults (FDA, EFSA): about 5 servings.
- Up to 200 mg at one time for healthy adults (EFSA): about 2 servings in one go.
- Up to 200 mg a day in pregnancy (EFSA, NHS): about 2 servings.
These are reference amounts for groups of people, not a personal limit. Some people feel jittery or sleep worse on much less. See the cutoff calculator for timing.
Good to know
USDA's recipe for iced coffee is 360 g of brewed coffee plus 111 g of ice, so part of each cup is ice rather than coffee.
How the serving amount was worked out: USDA lists 31 mg per 100 g; 240 g × 0.31 = 74.4 mg; 360 g × 0.31 = 111.6 mg.
Iced coffee vs other coffee drinks
- Brewed coffee: Iced coffee has less caffeine than brewed coffee per 8 fl oz cup (240 g): 74.4 mg vs 94.8 mg.
- Instant coffee: Iced coffee has more caffeine than instant coffee per 8 fl oz cup (240 g): 74.4 mg vs 62.4 mg.
- Cold brew coffee: Iced coffee has less caffeine than cold brew coffee per 8 fl oz cup (240 g): 74.4 mg vs 234.6–291.5 mg.
Common questions
How much caffeine is in Iced coffee?
USDA Agricultural Research Service, FoodData Central (FNDDS) gives 74.4 mg of caffeine per 8 fl oz cup (240 g). Other sizes are in the table on this page.
How many Iced coffee servings can I have in a day?
The FDA and EFSA cite up to 400 mg of caffeine a day, from all sources combined, for most healthy adults. At 74.4 mg per 8 fl oz cup (240 g), that is about 5 servings if Iced coffee is your only source. In pregnancy the reference is 200 mg a day.
How late can I drink Iced coffee?
With an 11:00 PM bedtime, our model suggests having one serving by about 7:25 PM for average metabolism, or 5:44 PM if you clear caffeine slowly. This is an estimate, not a rule.
Does Iced coffee have more caffeine than Brewed coffee?
Iced coffee has less caffeine than brewed coffee per 8 fl oz cup (240 g): 74.4 mg vs 94.8 mg.
How long does Iced coffee stay in your system?
Of the 74 mg in one 8 fl oz cup (240 g), roughly 37 mg remains after 5 hours and 19 mg after 10 hours with our average 5-hour half-life. From fast to slow metabolism, 10 hours later it is between 7 and 31 mg.
Where the number comes from
- Iced Coffee, brewed. USDA Agricultural Research Service, FoodData Central (FNDDS). FDC ID 2710428, nutrient "Caffeine" (262): portions "1 cup (8 fl oz)" = 240 g and "1 small" = 360 g; recipe ingredients. Accessed 2026-10-02. Source ↗
Recipes and labels change. If a number here no longer matches the label, the label wins.
General information, not medical advice
If you feel unwell after caffeine — for example chest pain, a fast or irregular heartbeat that does not settle, fainting, confusion or trouble breathing — get urgent medical help. If you are pregnant, take medication or have a heart, liver or anxiety condition, ask a doctor or pharmacist what amount is right for you.
Sources
- U.S. Food and Drug Administration (2024). Spilling the Beans: How Much Caffeine is Too Much? FDA Consumer Updates. fda.gov ↗
- European Food Safety Authority. Caffeine | EFSA. EFSA topic page (summary of the 2015 Scientific Opinion on the safety of caffeine). efsa.europa.eu ↗
- NHS. Foods to avoid in pregnancy. NHS. nhs.uk ↗
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