UK · Coffee & café
How much caffeine is in Greggs Flat White?
Greggs does not measure caffeine. Which? says Greggs supplied these indicative supplier figures as a guide, not an exact measure.
Which? reported an indicative 150 mg for a 222 ml Greggs flat white in August 2026; it is a supplier guide, not an exact measurement.
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Source and provenance
- Source type
- Independent publisher
- Market
- UK
- Value basis
- Reported by independent comparison
- Source reviewed
- 4 September 2026
- Source version/date
- 25 August 2026
Which? says it asked five chains for caffeine information and used online guides; many figures were obtained through brand press offices. The brand’s public UK menu does not publish this value, so treat it as a reported figure rather than a first-party public listing.
Estimated caffeine remaining over time
These figures apply CaffCalc’s exponential model to the adjusted 150 mg starting value. They are calculations, not measurements of caffeine in a particular person.
| Hours elapsed | 3-hour half-life | 5-hour half-life | 7-hour half-life |
|---|---|---|---|
| 0 | 150 mg | 150 mg | 150 mg |
| 3 | 75 mg | 99.0 mg | 111.4 mg |
| 5 | 47.2 mg | 75 mg | 91.4 mg |
| 8 | 23.6 mg | 49.5 mg | 67.9 mg |
| 10 | 14.9 mg | 37.5 mg | 55.7 mg |
| 12 | 9.4 mg | 28.4 mg | 45.7 mg |
With the central five-hour model, the estimate falls below 25 mg after approximately 12.9 hours. The faster and slower columns show why one fixed clearance time should not be treated as a personal fact.
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