Pick the decaf you drink, the cup size and how many a day. You see the caffeine per cup by every published or measured figure — the FDA’s range, two lab studies that measured real decaf coffees and teas, and Mayo Clinic’s table — scaled to your cup, and what your day adds up to.
Brewed decaf coffee has
Up to 15 mg in an 8 fl oz cup 0–15 mg across the sources · a regular brewed coffee is 96 mg
2 cups a day: 0–30 mg — at the top of the range, 7.5% of the 400 mg the FDA cites for most adults.
Even at the top of the range, it takes 6.4 cups of decaf to reach the caffeine of one regular brewed coffee (96 mg, Mayo Clinic).
Per cup, by source
- the FDA, decaf coffee, typically: 2–15 mg per 8 fl oz
- McCusker et al. (2006), 10 decaf coffees from different coffee shops, measured: 0–13.9 mg per 16 fl oz → 0–7 mg in 8 fl oz (scaled by volume)
- McCusker et al. (2006), 6 Starbucks brewed decafs from one shop, measured: 12–13.4 mg per 16 fl oz → 6–6.7 mg in 8 fl oz (scaled by volume)
- Mayo Clinic, brewed decaf: 1 mg per 8 fl oz
Decaf is not caffeine-free. The FDA: “Decaffeinated coffees and teas have less caffeine than their regular counterparts, but still contain some caffeine.”
This is not medical advice. If a doctor has told you to avoid caffeine — or you are pregnant or breastfeeding — the FDA: “If you are concerned about a condition or medication, or if you’re pregnant, trying to become pregnant, or breastfeeding, we recommend talking to your health care provider about whether you need to limit caffeine consumption.” Talk to your doctor or pharmacist, especially if you take medicine that caffeine can affect.
An 8 fl oz cup of decaf coffee holds about 2 to 15 mg of caffeine, the FDA says, and lab measurements agree: decaf coffees bought at 10 coffee shops held 0 to 13.9 mg per 16 oz, a decaf espresso 3.0 to 15.8 mg a shot, and decaf teas under 12 mg a serving. A regular 8 oz coffee is 96 mg.
How to use it
Pick the decaf you drink — brewed coffee, espresso, instant or tea — the size of your cup and how many a day. You see the caffeine per cup by every source, each named, scaled to your cup (a figure printed for 16 fl oz is halved for an 8 fl oz cup, and the checker says so), the range your day adds up to, and how many decafs it takes to reach one regular cup. It prints the spread the sources print — never one number of ours.
Decaf is not caffeine-free
The FDA: “Decaffeinated coffees and teas have less caffeine than their regular counterparts, but still contain some caffeine.” “For example, decaf coffee typically has 2 to 15 milligrams in an 8-fluid-ounce cup.” A 2006 study in the Journal of Analytical Toxicology went and measured: “The 10 decaffeinated coffee samples from different outlets contained caffeine in the range of 0-13.9 mg/16-oz serving.” “The caffeine content for the Starbucks espresso and the Starbucks brewed samples collected from the same outlet were 3.0-15.8 mg/shot and 12.0-13.4 mg/16-oz serving, respectively.” Its authors wrote it for people told to cut caffeine: “Despite widespread availability, various medical conditions necessitate caffeine-restricted diets.” “Patients vulnerable to caffeine effects should be advised that caffeine may be present in coffees purported to be decaffeinated.”
The figures, by source
| Drink — source | As printed | In 8 fl oz (or a shot) |
|---|---|---|
| Brewed decaf coffee — the FDA | 2–15 mg per 8 fl oz | 2–15 mg |
| Brewed decaf coffee — McCusker et al. 2006, 10 coffee shops | 0–13.9 mg per 16 fl oz | 0–7 mg |
| Brewed decaf coffee — McCusker et al. 2006, one Starbucks, 6 cups | 12–13.4 mg per 16 fl oz | 6–6.7 mg |
| Brewed decaf coffee — Mayo Clinic | 1 mg per 8 fl oz | 1 mg |
| Decaf espresso — McCusker et al. 2006, one Starbucks, 6 shots | 3–15.8 mg a shot | 3–15.8 mg |
| Decaf espresso — Mayo Clinic | 1 mg a shot | 1 mg |
| Instant decaf coffee — Mayo Clinic | 2 mg per 8 fl oz | 2 mg |
| Decaf tea — Chin et al. 2008 | under 12 mg per 6 fl oz | under 16 mg |
| Decaf black tea — Mayo Clinic | 2 mg per 8 fl oz | 2 mg |
Mayo Clinic’s table (by Mayo Clinic Staff, February 2025) prints one figure per drink — a regular brewed coffee 96 mg, an espresso 63, instant 62, brewed black tea 48 — and says: “Use these numbers as a guide.” The 2008 tea study measured 20 commercial teas: “The decaffeinated teas contained less than 12 mg of caffeine per serving, and caffeine was not detected in the herbal tea varieties.” Its servings were 6 or 8 oz, so the checker scales its top from the smaller 6 oz — the most a cup could hold by that study. “In most instances, the 6- and 8-oz serving sizes contained similar caffeine concentrations per ounce, but the steep-time affected the caffeine concentration of the tea.”
Why no USDA figure? USDA FoodData Central lists brewed decaf coffee, decaf espresso and brewed decaf black tea at 1 mg per 100 g, but each is coded “Based on another form of the food or similar food”, and decaf green tea’s 0 mg “Other procedure used from imputing” — worked out, not measured, so they are not used as measurements here.
Is there a legal limit?
In the EU, an instant coffee may be labelled decaffeinated only “provided that the anhydrous caffeine content does not exceed 0,3 % by weight of the coffee-based dry matter” (Directive 1999/4/EC). The FDA’s page gives a typical range rather than a limit. Either way, the label “decaf” means less caffeine, not none.
Worked examples
- Two 8 fl oz cups of brewed decaf (the page’s example): up to 15 mg a cup, 0–30 mg a day — at the top of the range 7.5% of the 400 mg the FDA cites for most adults. It takes 6.4 cups of decaf to reach one regular cup’s 96 mg.
- Three 16 fl oz decafs from a coffee shop: up to 30 mg a cup and 90 mg a day at the top of the range.
- Two decaf espresso shots: 1–15.8 mg a shot, up to 31.6 mg a day; 3.9 decaf shots make one regular espresso’s 63 mg.
- Four 8 fl oz cups of decaf tea: up to 16 mg a cup by the 2008 study, up to 64 mg a day.
Common mistakes
- Counting decaf as zero. Five decafs a day at the top of the range is 75 mg — closer to a regular cup than to nothing.
- Using a cup size that is not yours. A 16 fl oz mug holds twice an 8 fl oz cup’s caffeine; the figures are per volume.
- Calling herbal tea decaf. The 2008 study found no caffeine in the herbal teas it measured — they are a different drink, not decaffeinated tea.
- Reading one brand as all decaf. The 2006 study’s decafs from 10 shops ran from 0 to 13.9 mg per 16 oz; the shop and the batch matter.
Frequently asked questions
How much caffeine is in decaf coffee?
The FDA: “decaf coffee typically has 2 to 15 milligrams in an 8-fluid-ounce cup.” Measured decafs from 10 coffee shops held 0 to 13.9 mg per 16 oz (McCusker et al., 2006).
Is decaf coffee caffeine free?
No. The FDA: “Decaffeinated coffees and teas have less caffeine than their regular counterparts, but still contain some caffeine.”
How much caffeine is in decaf tea?
The 2008 study of 20 commercial teas: “The decaffeinated teas contained less than 12 mg of caffeine per serving”. Mayo Clinic’s table prints 2 mg for an 8 oz cup of decaf black tea.
Does decaf tea have caffeine?
Yes, a little — under 12 mg a serving in the 2008 measurements. Herbal teas had none.
How much caffeine is in a decaf espresso?
Six decaf espressos from one Starbucks measured 3.0 to 15.8 mg a shot (McCusker et al., 2006); Mayo Clinic’s table prints 1 mg for a 1 oz decaf espresso.
How many cups of decaf equal one cup of coffee?
At the top of the FDA’s range, 15 mg, it takes 6.4 cups of decaf to reach the 96 mg of a regular 8 oz cup in Mayo Clinic’s table; at the low end, many more.
Can I drink decaf if I have to avoid caffeine?
That is a question for your doctor, who knows why you were told to avoid it. The 2006 study’s authors: “Patients vulnerable to caffeine effects should be advised that caffeine may be present in coffees purported to be decaffeinated.”
More caffeine tools: the Caffeine Content Chart for your whole day’s drinks, the Caffeine Half-Life & Sleep Cutoff Calculator for when the last cup clears, and Tea Caffeine vs Coffee.
How your decaf was decaffeinated — Swiss Water, CO2, ethyl acetate or methylene chloride, and the US rule behind each: the Decaf Process Checker.
Read next
- Caffeine as a nootropic: benefits, dose and side effects
- Is there caffeine in nootropics?
- Can you take Mind Lab Pro with coffee?
- Do nootropics affect sleep?
This is not medical advice. If a doctor has told you to limit caffeine, or you are pregnant or breastfeeding, ask them how much decaf fits — the FDA: “If you are concerned about a condition or medication, or if you’re pregnant, trying to become pregnant, or breastfeeding, we recommend talking to your health care provider about whether you need to limit caffeine consumption.” Some links on this site are affiliate links: I buy what I review at full price, and a commission never changes a verdict.