Caffeine in drinks
How much caffeine is in Decaf coffee?
Data checked against the source on 2026-10-03 by Oleksii Y.
One 8 fl oz cup of Decaf coffee has 2–15 mg of caffeine, according to U.S. Food and Drug Administration.
How Decaf coffee compares
- Strength: 3.6 mg per 100 ml (middle of the range).
- One 8 fl oz cup has as much caffeine as less than a sixth 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, 11 have more caffeine per serving and 2 have less.
How much will be left at bedtime?
1 × 8 fl oz cup of Decaf coffee (middle of the range)
Left at 11:00 PM (8 h later), average metabolism
≈ 3 mg
Range 1–5 mg (fast to slow metabolism)
9 mg is already at or under the 50 mg this tool aims to have left at bedtime.
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
How long does Decaf 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 of Decaf coffee (9 mg), about 5 mg is still in your body 5 hours later and about 2 mg after 10 hours. If you clear caffeine slowly (an 8-hour half-life), about 4 mg is left after 10 hours.
Estimated caffeine left at 11:00 PM from one 8 fl oz cup (9 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) | ≈ 1 mg | 0–2 mg |
| 12:00 PM (11 h before bed) | ≈ 2 mg | 1–3 mg |
| 3:00 PM (8 h before bed) | ≈ 3 mg | 1–5 mg |
| 6:00 PM (5 h before bed) | ≈ 5 mg | 3–6 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 26 servings.
- Up to 200 mg at one time for healthy adults (EFSA): about 13 servings in one go.
- Up to 200 mg a day in pregnancy (EFSA, NHS): about 13 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
In a lab study, 10 decaf coffees bought from different outlets contained 0 to 13.9 mg of caffeine per 16 oz serving.
Decaf coffee vs other decaf drinks
- Decaf instant coffee: Decaf coffee has more caffeine than decaf instant coffee per 8 fl oz cup: 2–15 mg vs 2.4 mg.
- Decaf black tea: Decaf coffee has more caffeine than decaf black tea per 8 fl oz cup: 2–15 mg vs 2.4 mg.
Common questions
How much caffeine is in Decaf coffee?
U.S. Food and Drug Administration gives 2–15 mg of caffeine per 8 fl oz cup.
How many Decaf 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 2–15 mg per 8 fl oz cup, that is about 26 servings if Decaf coffee is your only source. In pregnancy the reference is 200 mg a day.
How late can I drink Decaf coffee?
One serving has about 9 mg, which is at or under the 50 mg our calculator aims to have left at bedtime, so it sets no cutoff for a single serving. Several servings add up.
How long does Decaf coffee stay in your system?
Of the 9 mg in one 8 fl oz cup, roughly 5 mg remains after 5 hours and 2 mg after 10 hours with our average 5-hour half-life. From fast to slow metabolism, 10 hours later it is between 1 and 4 mg.
Where the number comes from
- Spilling the Beans: How Much Caffeine Is Too Much? U.S. Food and Drug Administration. Section "'Decaffeinated' Does Not Mean Caffeine-free": "decaf coffee typically has 2 to 15 milligrams in an 8-fluid-ounce cup" Accessed 2026-10-02. Source ↗
- Caffeine content of decaffeinated coffee. Journal of Analytical Toxicology. PMID 17132260, abstract. 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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