Coffee Caffeine Calculator
Pick your brew method and cup size to see how much caffeine is in a cup of coffee — the total mg, the mg in a standard 8 fl oz serving, and how much of the FDA's 400 mg daily guidance that uses. Typical values, not a measurement of your specific cup.
Caffeine in this cup
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Caffeine in this cup
— mg
- Per 8 fl oz (240 ml)
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- Typical range for this cup
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- Share of FDA 400 mg / day
A typical value, not a measurement. Real cups move with the beans, the dose of grounds, the grind and the brew time.
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How much caffeine is in a cup of coffee
How much caffeine is in a cup of coffee depends far more on how it was brewed than on which beans went in. A standard 8 fl oz (240 ml) cup holds roughly 95 mg from drip or filter coffee, 107 mg from a French press, 112 mg percolated, 100 mg from ready-to-drink cold brew and 62 mg from instant. The calculator takes the figure for your brew method and scales it to the size you actually drink, because almost nobody drinks 8 fl oz — a 16 oz to-go cup of drip coffee is around 190 mg.
Those are typical values rather than measurements. Drip coffee alone commonly lands anywhere between 70 mg and 140 mg per 8 fl oz depending on the dose of grounds, the grind, the water temperature and how long the water and coffee stay in contact. The calculator also assumes a bigger cup is simply more of the same coffee, which holds for a refill but not for a cafe drink that adds milk or a second shot. Read the result as the middle of a band.
The FDA describes 400 mg a day — about four 8 fl oz cups of drip coffee — as an amount not generally associated with negative effects for healthy adults, and that is the figure the share row compares against. Decaf is not zero: it keeps about 3 mg per 8 fl oz, so the calculator switches to that figure for every brew method when you turn decaf on.
caffeine (mg) = mg per 8 fl oz for the brew method × (cup size ÷ 8 fl oz) Typical composition values, not a measurement of the cup in front of you, and not medical advice. Espresso is measured per 1 fl oz shot rather than per cup, so it is not in the brew method list — the espresso caffeine calculator covers it.
USDA FoodData Central ↗FDA: Spilling the Beans — How Much Caffeine is Too Much ↗
Caffeine in coffee FAQ
How much caffeine is in a cup of coffee?
About 95 mg in a standard 8 fl oz (240 ml) cup of drip or filter coffee. A French press cup is around 107 mg, percolated around 112 mg, ready-to-drink cold brew around 100 mg and instant around 62 mg. Real mugs are usually bigger than 8 fl oz, which is why the calculator scales the figure to the cup size you enter.
Does dark roast coffee have more caffeine than light roast?
Barely, and not in the direction most people expect. Per gram of coffee, light and dark roasts hold almost the same amount of caffeine — roasting destroys very little of it. Dark roast beans lose more water and mass during roasting, so a scoop measured by volume holds slightly less coffee and therefore marginally less caffeine. The gap is small enough that roast is not a useful input, which is why this calculator has no roast setting. How much coffee you use and how you brew it matter far more.
How much caffeine is in decaf coffee?
Around 3 mg per 8 fl oz. Decaffeination removes most of the caffeine but not all of it, so decaf is low-caffeine rather than caffeine-free. Even a large decaf stays in single-digit milligrams, which is a small fraction of a regular cup, but it is not nothing if you are extremely sensitive.
Why do published caffeine figures for the same coffee vary so much?
Because a cup of coffee is not a standardised product. The ratio of grounds to water, the grind size, the water temperature, the contact time and the bean itself all move the result. Drip coffee measured across real samples commonly runs from 70 mg to 140 mg per 8 fl oz. Treat any single number, including this one, as the centre of a range.
Is 400 mg of caffeine a day a safe limit?
The FDA describes 400 mg a day as an amount not generally associated with negative effects for healthy adults — roughly four 8 fl oz cups of drip coffee. It is a general guideline, not a personal limit. Sensitivity varies widely between people, and pregnancy, certain medications and some medical conditions change the picture. Ask a clinician about your own limit.