Reducing caffeine · Practical guide
Decaf Coffee vs Decaf Tea: Which Has Less Caffeine?
The short answer
Neither decaf coffee nor decaf tea is automatically caffeine-free. There’s no universal winner across brands and preparations. Compare a documented finished serving, not a dry-leaf percentage with a whole-cup coffee value.
These Costa figures are from the guide for 30 April–26 August 2026. We haven’t checked a newer recipe yet, so ask Costa or check the latest menu if you need the current amount.
| Evidence | What it supports | What it doesn’t tell us |
|---|---|---|
| FDA decaf coffee example | Typically 2–15 mg per 8 US fl oz cup | A value for every brand, size or UK café |
| Costa dated recipe | 2 mg for the named 2 shots / 1 pod serving | A whole large coffee from any café |
| Twinings UK FAQ | Residual caffeine remains; the FAQ discusses dry leaf and a typical teabag | An exact measured brewed dose for every tea or brewing time |
Range, finished serving and dry ingredient figures have different denominators. No numeric decaf tea entry is added to the calculator from this evidence.
Compare the serving sizes
These figures come from the sources linked below. Your drink may vary, and recipes can change, so check the latest label or menu if you need an exact amount.
| Drink / market | Serving | Caffeine | Per 100 ml | Evidence / action |
|---|---|---|---|---|
| Costa Decaf coffeeUK | 2 shots / 1 pod | 2 mg | Not documented | Manufacturer listedVerified source record · Reviewed 2026-08-23Use this dose · Compare |
Bars use the selected measure; numbers remain visible in both units. No bar is drawn for an unknown concentration. Per 100 ml = serving caffeine × 100 ÷ listed volume.
The practical difference is the starting product
Decaf coffee begins with coffee and decaf tea with tea. Both have undergone caffeine reduction; the label isn’t a claim that every trace is absent. Taste, recipe and preparation can differ, but this guide compares caffeine evidence rather than claiming that one category is healthier or suitable for everyone.
A range isn’t a product measurement
The FDA gives a typical decaf coffee example rather than a certified value for a named bag of beans or UK café order. A documented café serving can sit within that broad range without establishing a number for a full mug prepared differently. Keep the serving and preparation attached to the amount when logging it.
Why a dry-leaf percentage isn’t milligrams in your cup
Twinings’ UK FAQ explains that its decaf teas retain some caffeine and discusses a typical teabag. Dry ingredient caffeine and brewed caffeine aren’t identical measurements: the amount of tea and extraction must also be known. This guide therefore doesn’t convert the FAQ into a universal brewed-tea calculator record.
Several small doses still add up
For illustration only, four servings at a hypothetical 3 mg each total 12 mg. That’s arithmetic, not a verified decaf tea value. Recording all known doses helps avoid accidentally treating small values as zero. Where a product is unknown, retain the uncertainty rather than choosing a reassuring number.
Herbal infusion and decaf tea are different labels
A pure peppermint infusion isn’t decaffeinated black tea. Blends can include true tea or other caffeine-containing ingredients, so inspect the complete ingredients and manufacturer statement. “Herbal” on the front of a package shouldn’t replace checking the actual blend.
How to choose without false precision
For a comparable decision, use the same finished portion and a product-specific source where available. Ask the manufacturer for brewed-cup data if that matters to you. A personal caffeine restriction or strong adverse reaction needs individual professional guidance; CaffCalc can’t certify a drink as appropriate for that situation.
Sources and notes
- Costa Coffee UK store guideGuide applies 30 April–26 August 2026. Source reviewed 2026-08-23.
- FDA: decaffeinated doesn’t mean caffeine-freeReviewed 24 October 2026. Typical decaf coffee example, not a UK brand measurement.
- Twinings UK FAQ: caffeine and decaffeinationReviewed 24 October 2026. Dry leaf and typical teabag statements aren’t relabelled as an exact brewed-cup dose.
Use this guide to compare drinks, not to make medical decisions. We have marked estimates and calculations so you can tell them apart from published amounts. Check the latest label or menu if you need an exact figure.