For most healthy adults, up to 400 milligrams (mg) of caffeine per day is generally considered safe as of 2024—roughly the amount in four 8-ounce cups..

A standard 8-ounce glass of black tea contains about 47–50 mg of caffeine, while green tea has up to 45 mg and white tea delivers under 30 mg.

A 16-ounce serving of cold brew typically contains around 200 mg of caffeine, though the amount can range from roughly 170 mg to over 300 mg.

A standard 8-ounce glass of sweet tea typically contains 15 to 70 mg of caffeine, with larger 16-ounce servings reaching up to 100 mg depending.

An 8-ounce cup of decaf coffee typically contains about 2 to 15 mg of caffeine, compared to 70 to 140 mg in a regular cup.

One standard serving of Café Bustelo Instant Espresso — one teaspoon dissolved in six ounces of water — contains approximately 60 to 90 mg.

An 85% dark chocolate bar has about 80 mg of caffeine per 100 grams (3.5 oz), or roughly 23 mg per one-ounce serving.

An 8-ounce glass of iced tea typically contains 20 to 70 mg of caffeine, depending on the tea type and brewing method.

For most healthy adults, up to 400 milligrams of caffeine per day—about four cups of brewed coffee—is generally considered safe for the heart.

A 12-ounce can of Coca-Cola Classic contains about 32 to 34 mg of caffeine. An 8-ounce glass holds roughly 21 mg.