Drink comparisons · Evidence-led guide
Does sugar-free mean caffeine-free? Read the full label
The short answer
No. Sugar and caffeine are different label attributes. A sugar-free drink can contain caffeine, while a caffeine-free variant needs its own explicit identification.
Inspect the documented servings
These values come from the linked catalogue records. A source-backed record is not a measurement of your drink or a guarantee of a current recipe.
| Drink / market | Serving | Caffeine | Per 100 ml | Evidence / action |
|---|---|---|---|---|
| Diet CokeUK | 330 ml can | 46 mg | 13.9 mg (calculated) | Manufacturer listedVerified source record · Reviewed 2026-08-21Use this dose · Compare |
| Coca-Cola Zero Sugar Zero CaffeineUK | 330 ml can | 0 mg | 0 mg (calculated) | Manufacturer listedVerified source record · Reviewed 2026-09-04Use this dose · Compare |
| Red Bull SugarfreeUK | 250 ml can | 80 mg | 32 mg (calculated) | Manufacturer listedVerified source record · Reviewed 2026-09-04Use this dose · Compare |
Bars use the selected measure; numbers remain visible in both units. No bar is drawn for an undocumented concentration. Per 100 ml = serving caffeine × 100 ÷ documented volume.
Zero what?
Read the complete name rather than stopping at “Zero”. Standard Coca-Cola Zero Sugar lists caffeine in the GB ingredients. The separately named Zero Sugar Zero Caffeine product is a different entry. Similarly, Pepsi UK distinguishes Max from Max No Caffeine.
Presence does not establish quantity
An ingredient list may confirm caffeine without stating milligrams. That is useful information, but it is not enough to calculate a dose. CaffCalc leaves unsupported amounts unknown rather than inferring them from sugar or calorie figures.
Decaf is another category
A decaf coffee is not interchangeable with a product explicitly described as caffeine-free. Use a documented decaf serving where available, retain small nonzero amounts, and avoid transferring one café’s preparation to another brand.
Sources and scope
- Coca-Cola Great Britain caffeine FAQGreat Britain FAQ and serving size. Source reviewed 2026-08-21.
- Coca-Cola Great Britain product announcementOfficial Great Britain announcement for the zero-caffeine variant, including the 330 ml can format. Source reviewed 2026-09-04.
- Red Bull GB Sugarfree caffeine Q&AOfficial Great Britain page; values are listed per complete can. Source reviewed 2026-09-04.
- Pepsi UK: Pepsi MaxReviewed 24 September 2026: caffeine appears in the ingredients; this page does not supply a numerical caffeine amount.
- Coca-Cola GB: Zero Sugar productsReviewed 24 September 2026: standard Zero Sugar lists caffeine flavouring. Do not confuse it with the Zero Caffeine variant.
Educational information, not medical advice. Published, calculated and approximate values have different limits. Check the current product label or recipe when an exact amount matters.