Iced coffee vs Dunkin' iced coffee: caffeine compared
Dunkin' iced coffee (24 oz (medium)) has 294 mg of caffeine, 109 mg more than Iced coffee (16 oz, 185 mg) — 1.6× as much per serving. Per fluid ounce, Dunkin' iced coffee is the stronger drink: 12.2 mg/oz versus 11.6 mg/oz.
| Iced coffee | Dunkin' iced coffee | |
|---|---|---|
| Serving | 16 oz | 24 oz (medium) |
| Caffeine per serving | 185 mg | 294 mg |
| Per fl oz | 11.6 mg | 12.2 mg |
| Share of 400 mg/day | 46% | 74% |
| Servings to reach 400 mg | 2.2 | 1.4 |
| Hours until under 50 mg | 9.4 h | 12.8 h |
| Last one for an 11 PM bedtime · standard (50 mg) | 1:34 PM | 10:13 AM |
| Last one for an 11 PM bedtime · sensitive (25 mg) | 8:34 AM | 5:13 AM |
| Share of the 200 mg pregnancy limit | 92% | 147% |
One serving of each, over 16 hours
Common questions
Which has more caffeine, Iced coffee or Dunkin' iced coffee?
Dunkin' iced coffee (24 oz (medium)) has about 294 mg versus 185 mg in Iced coffee (16 oz): 109 mg more, or 1.6× as much.
Which is stronger per ounce, Iced coffee or Dunkin' iced coffee?
Dunkin' iced coffee: about 12.2 mg per fl oz versus 11.6 mg for Iced coffee. Serving size decides the total you actually drink.
How many Iced coffee servings equal one Dunkin' iced coffee?
About 1.6 servings of Iced coffee (16 oz) match the caffeine in one Dunkin' iced coffee (24 oz (medium)).
When should I stop drinking Iced coffee or Dunkin' iced coffee before bed?
For an 11 PM bedtime with a 50 mg limit and a 5-hour half-life: last Iced coffee by 1:34 PM, last Dunkin' iced coffee by 10:13 AM. Half-life varies from about 1.5 to 9.5 hours between people.
Method
Caffeine per labeled serving, from the same drink table every calculator here uses (FDA/USDA reference amounts and manufacturer labels; see caffeine content of every drink). Brewed drinks vary batch to batch, so read these as typical values. Decay uses a 5-hour average half-life with a 45-minute absorption ramp; cutoff = bedtime − 5 h × log₂(dose ÷ limit). Percentages use the FDA's 400 mg/day figure for healthy adults and the 200 mg/day limit ACOG gives for pregnancy.
Source — Iced coffee: CSPI caffeine chart (Starbucks Iced Coffee, 16 oz grande), checked 2026-10-13. Typical value from Starbucks' grande iced coffee.
Unverified — Dunkin' iced coffee: Dunkin' figure not confirmed on an official or reference source. Treat 294 mg as a rough estimate.