Coffee Calculators

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Caffeine Content Calculator

Caffeine in the cup is dose times how much of the alkaloid you actually extract. Arabica sits near 1.2% by dry mass; robusta is roughly twice that. Espresso extracts a smaller share of a small dose; filter and cold brew pull longer. This is order-of-magnitude milligrams, not a blood test.

Inputs

Units
g

How completely that dose is typically extracted, not cup size.

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Results

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Calculation method

Milligrams are dry dose times milligrams of caffeine per gram of that species times how much of it the brew usually recovers. Robusta roughly doubles arabica. A regular espresso recovers about 65–70% of bean caffeine (Ludwig / Crozier); this page uses 0.70. Filter with more water and time recovers more of the same dose (0.85). A long cold steep of that same dose is treated the same as filter — papers do not show less caffeine ‘because it is cold’. 18 g arabica espresso is about 151 mg, the same dose as filter or cold brew about 184 mg. Decaf is not an option here: it still carries a little caffeine, usually a few milligrams per cup, and this estimate does not model it.

Exact formula

caffeineMg = doseG × mgPerG × extraction. Arabica 12 mg/g (~1.2%), robusta 22 mg/g; filter 0.85, espresso 0.70, cold brew 0.85. Limits: Origin, roast, grind and steep time omitted; long cold steep is not weaker because it is cold (Fuller & Rao 2017). Not a laboratory assay.

Blends

A 20% robusta espresso blend sits between the two species: 0.8 × 12 + 0.2 × 22 = 14 mg/g. Weight the estimate; this select is 0 or 100%.

Daily total

Add shots and afternoon filter separately. The daily-limit tool is the population guideline; this page is one drink.

Frequently asked questions

Is a double shot more caffeine than a mug of filter?

Often no. Filter uses more dry coffee in the mug. Compare doses, not cup names.

Dark roast has less caffeine?

A little mass is lost to roast, but a gram of dark still has most of the alkaloid. Dose mass matters more than colour folklore.

Can I add milk?

Milk does not remove caffeine. It only changes the cup size you sip.

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