Mix regular and decaf your way — scoops of each, or shots — then pick the cup and how many a day. You see the caffeine by every published figure, each named and scaled to your cup, Mayo Clinic’s one figure, and your day beside the 400 mg the FDA cites for most adults.
Your half-caff, 1 : 1 (50% decaf), has
38–90 mg in an 8 fl oz cup Mayo Clinic’s figures: 49 mg · the same cup all regular: 75–165 mg
2 cups a day: 75–180 mg — at the top of the range, 45% of the 400 mg the FDA cites for most adults.
By Mayo Clinic’s figures that is 49% less caffeine than the same cup all regular (96 mg).
How it is worked out: 50% of the grounds are regular, so 50% of a regular cup’s caffeine plus 50% of a decaf cup’s — it assumes both coffees brew the same way.
Folgers Half Caff is “made with a blend of 50% decaffeinated coffee” — a 1 : 1 mix, like this one. Its pages print no milligram figure, only “*Caffeine levels may vary.”
Per 8 fl oz cup, by source
- Regular — the FDA, regular brewed coffee: 113–247 mg per 12 fl oz → 75–165 mg in 8 fl oz (scaled by volume)
- Regular — USDA FoodData Central, brewed coffee: 40 mg per 100 g × 29.6 g a fl oz → 95 mg in 8 fl oz
- Regular — Mayo Clinic, brewed coffee: 96 mg per 8 fl oz
- Decaf — the FDA, decaf coffee, typically: 2–15 mg per 8 fl oz
- Decaf — 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)
- Decaf — 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)
- Decaf — Mayo Clinic, brewed decaf: 1 mg per 8 fl oz
This is not medical advice. If a doctor has told you to limit 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.
A half-caff cup — half regular coffee, half decaf — holds about half a regular cup’s caffeine: 38–90 mg in 8 fl oz by the published figures, 49 mg by Mayo Clinic’s table (regular brewed 96 mg, decaf 1 mg). Folgers sells its Half Caff as “made with a blend of 50% decaffeinated coffee” and prints no milligram figure.
How to use it
Pick your coffee — brewed, espresso shots or instant — then how much regular and how much decaf goes in. Scoops, tablespoons or grams all work, as long as both are counted the same way; for espresso, type the shots of each. Add the cup size and how many cups a day. You see the cup’s caffeine across every published figure, Mayo Clinic’s one figure, the same cup all regular, and your day beside the 400 mg the FDA cites for most adults. Every source is listed under the answer, scaled to your cup.
How the arithmetic works
If half the grounds are decaf, the cup gets half a regular cup’s caffeine plus half a decaf cup’s. The calculator does exactly that with each source’s regular and decaf figures, so the answer is the spread those sources print — never one number of ours. It assumes both coffees brew the same way: the same grind, water and time. A darker or lighter roast, a stronger brew or a different bean moves the real cup, which is why the FDA’s range for a regular 12 fl oz brewed coffee runs from 113 to 247 mg — “Coffee, regular brewed non-specialty: 113 to 247 milligrams” — and why the low end of the answer is far from the high end.
The regular cup comes from three places: the FDA’s range, USDA FoodData Central (40 mg per 100 g of brewed coffee, about 95 mg in 8 fl oz) and Mayo Clinic’s table (96 mg). The decaf cup comes from the FDA (“For example, decaf coffee typically has 2 to 15 milligrams in an 8-fluid-ounce cup.”), a 2006 lab study that measured decaf from 10 coffee shops (“The 10 decaffeinated coffee samples from different outlets contained caffeine in the range of 0-13.9 mg/16-oz serving.”), and Mayo Clinic’s table (1 mg). The same figures run the Caffeine Content Chart and the Decaf Caffeine Checker.
Half-caff caffeine, by mix and cup
| Mix and cup | Across the sources | Mayo Clinic’s figures | The same, all regular |
|---|---|---|---|
| 3 : 1 (25% decaf), 8 fl oz | 57–127 mg | 72 mg | 75–165 mg |
| 3 : 1 (25% decaf), 12 fl oz | 85–191 mg | 108 mg | 113–247 mg |
| 3 : 1 (25% decaf), 16 fl oz | 113–255 mg | 145 mg | 151–329 mg |
| 1 : 1 (50% decaf), 8 fl oz | 38–90 mg | 49 mg | 75–165 mg |
| 1 : 1 (50% decaf), 12 fl oz | 57–135 mg | 73 mg | 113–247 mg |
| 1 : 1 (50% decaf), 16 fl oz | 75–180 mg | 97 mg | 151–329 mg |
| 1 : 3 (75% decaf), 8 fl oz | 19–52 mg | 25 mg | 75–165 mg |
| 1 : 3 (75% decaf), 12 fl oz | 28–79 mg | 37 mg | 113–247 mg |
| 1 : 3 (75% decaf), 16 fl oz | 38–105 mg | 50 mg | 151–329 mg |
| Espresso, 1 regular + 1 decaf shot | 64–79 mg | 64 mg | 126 mg |
| Espresso, 2 regular + 1 decaf shot | 127–142 mg | 127 mg | 188–189 mg |
| Espresso, 1 regular + 2 decaf shots | 65–95 mg | 65 mg | 188–189 mg |
3 : 1 is a quarter decaf, 1 : 1 the usual half-caff, 1 : 3 three-quarters decaf. Mayo Clinic’s table prints one figure per drink and says: “Use these numbers as a guide.”
Half-caf espresso
A café half-caf is usually a double made of one regular shot and one decaf shot. By the published figures that is 64–79 mg: a regular shot is 63 mg in Mayo Clinic’s table (USDA’s per-100 g figure gives the same 63 mg for a 1 fl oz shot), and a decaf shot is 1 mg in Mayo Clinic’s table or 3.0 to 15.8 mg measured — “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.” Two regular shots would be 126 mg.
The brands that sell it
Folgers sells Half Caff ground coffee and K-Cup pods. Its ground coffee page: “Enjoy the smooth, clean and balanced flavor of Folgers® Half Caff ground coffee, made with a blend of 50% decaffeinated coffee*.” The pods: “Folgers® Half Caff Coffee is made with 50% decaffeinated coffee*, so you can enjoy your favorite cup of coffee any time.” with the footnote “*Caffeine levels may vary.” Neither page prints a milligram figure, so this calculator does not invent one: a 1 : 1 mix brewed like a regular cup lands where the table above says.
Worked examples
- Two 8 fl oz half-caffs a day (the calculator’s example): 38–90 mg a cup, 75–180 mg a day — at the top of the range 45% of the 400 mg the FDA cites for most adults.
- Three 16 fl oz half-caffs: 75–180 mg a cup and 226–539 mg a day, 135% of 400 mg at the top of the range — a big mug of half-caff can add up to more than people expect.
- Two half-caf doubles (one regular, one decaf shot each): 64–79 mg a drink, 128–158 mg a day.
- A quarter-caff, 1 : 3, in a 12 fl oz cup twice a day: 28–79 mg a cup, 57–157 mg a day.
- Three cups of 1 : 1 instant: 32 mg a cup — Mayo Clinic prints 62 mg for regular instant and 2 mg for decaf — 96 mg a day.
Common mistakes
- Reading half-caff as “half of my usual”. It is half of a regular cup of the same size: a 16 fl oz half-caff by the FDA’s range can hold more than a strong 8 fl oz regular.
- Counting the decaf half as zero. Decaf still has some caffeine — the FDA: “Decaffeinated coffees and teas have less caffeine than their regular counterparts, but still contain some caffeine.”
- Mixing by different measures. One scoop of regular and one tablespoon of decaf is not 1 : 1. Count both the same way.
- Using a cup size that is not yours. A 12 fl oz mug holds half again an 8 fl oz cup’s caffeine — 113–247 mg for a regular 12 fl oz cup by the FDA’s range.
Frequently asked questions
How much caffeine is in half caff coffee?
An 8 fl oz half-caff (1 : 1) holds 38–90 mg by the published figures, 49 mg by Mayo Clinic’s table — about half a regular cup’s caffeine.
What is half caff coffee?
Coffee brewed from regular and decaf mixed half and half, or a café drink made with one regular and one decaf shot. Folgers’ Half Caff is “made with a blend of 50% decaffeinated coffee”.
Does half caff have half the caffeine?
About half of a regular cup of the same size, plus a little from the decaf half: by Mayo Clinic’s figures an 8 fl oz half-caff has 49% less caffeine than the same cup all regular.
How much caffeine is in a half-caf espresso?
One regular and one decaf shot: 64–79 mg by the published figures, against 126 mg for two regular shots.
How much caffeine is in Folgers Half Caff?
Folgers does not print a milligram figure; its pods carry the footnote “*Caffeine levels may vary.” As a 1 : 1 blend brewed like a regular cup, it lands in the table above: 38–90 mg in 8 fl oz.
How do I make half caff at home?
Mix regular and decaf grounds in the share you want and brew as usual — 1 : 1 for half-caff, 1 : 3 for a quarter. The calculator shows what each mix holds.
Can I drink half caff if I have to cut caffeine?
That is a question for your doctor, who knows why you were told to cut it. The 2006 decaf 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 Decaf Caffeine Checker for decaf alone, the Caffeine Content Chart for your whole day’s drinks, and the Caffeine Half-Life & Sleep Cutoff Calculator for when the last cup clears.
Read next
- Caffeine as a nootropic: benefits, dose and side effects
- Can you take Mind Lab Pro with coffee?
- Is there caffeine in nootropics?
- 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 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.” Talk to your doctor or pharmacist, especially if you take medicine that caffeine can affect. Some links on this site are affiliate links: I buy what I review at full price, and a commission never changes a verdict.