Cold Brew vs Iced Coffee: Which Has More Caffeine?

The myth and the measurement

Cold brew steeps coarse grounds in cold water for 12–24 hours, and people assume the long steep multiplies caffeine. Measured, ready-to-drink cold brew lands around 100 mg per 8 oz — essentially the same as hot drip coffee (~96 mg). Caffeine extraction in cold water is somewhat less efficient per minute, and the long steep mostly makes up the difference rather than doubling it.

Where cold brew runs away is concentrate: undiluted homemade concentrate can run several hundred mg per 8 oz, and how much water or milk you cut it with decides the final number. Store-bought RTD bottles solve this for you — the label is the truth.

Chain numbers, side by side

Starbucks grande cold brew: 205 mg. Their grande iced coffee: 165 mg. Dunkin 14 oz cold brew: about 197 mg; their 24 oz iced medium: 297 mg — container size, again, does more work than brewing method. Starbucks' nitro cold brew (280 mg grande) tops both menus because nitrogen lets them skip ice and serve a denser drink.

The practical read: at chain sizes, cold brew beats iced coffee by roughly 15–25% — meaningful, not the 2x folklore suggests.

Acidity and feel are the real difference

Cold brew's lower acidity is why many people find it gentler on the stomach — that's a chemistry difference, not a caffeine one. Iced coffee, being brewed hot and chilled, keeps more of the bright, acidic compounds. For bedtime planning, treat a cold brew like any equivalently-dosed coffee: a grande at 3 PM leaves roughly 50 mg active at 10 PM for an average metabolizer. Use the calculator with the exact numbers from the drink pages.