How much caffeine is in a cup of coffee?

It depends mostly on the dose. A 12 g filter mug estimates at roughly 67 to 160 mg on CupTune's model, and a double espresso from 18 g at roughly 101 to 239 mg. The range is wide because bean species and extraction both vary.

Does espresso have more caffeine than filter coffee?

Per millilitre, yes. Per serving, usually not: a double espresso uses about 18 g of coffee and a large filter mug can use more. Comparing servings compares doses, not methods.

Does dark roast have less caffeine?

The evidence is genuinely mixed. A 2024 study found dark roasts gave lower caffeine under identical brewing conditions but higher caffeine at identical extraction yields, and noted that decades of conflicting methodology have prevented a general conclusion.

How much coffee is too much?

The FDA cites 400 mg a day as not generally associated with negative effects for most healthy adults, while stressing that sensitivity varies widely between people. It is a reference point, not a personal limit, and CupTune is not a source of medical advice.

Why nobody can tell you a number

How much caffeine is in your coffee

The honest answer to how much caffeine is in your coffee is a range, and the width of that range is the interesting part.

CupTune's estimated ranges by serving. Each bar is a range because dose and bean species move the result by more than a factor of two.

Dose is the biggest lever

Caffeine in your cup comes overwhelmingly from two things: how many grams of coffee you used, and what species those beans were. Arabica typically runs somewhere near 0.8–1.4 per cent caffeine by dry mass and robusta roughly twice that. Caffeine is very water-soluble, so most of it comes out in an ordinary brew regardless of method.

That is why a "cold brew has more caffeine than espresso" headline is usually just comparing a 65 g batch with a 9 g shot. It is a statement about the dose, dressed up as a statement about the method. You can look up per-serving reference figures in USDA FoodData Central caffeine values, but they describe typical products rather than your cup.

The roast argument is not settled

Light roast has more caffeine, says one camp. Dark roast has more, says the other. A 2024 Scientific Reports study of roast level and brewed caffeine put it plainly: the effect of roast on brewed caffeine has been studied for decades and conflicting methodologies have muddled any general conclusion. That study found that under identical brewing conditions dark roasts generally gave lower caffeine concentrations than light and medium roasts — but at identical extraction yields, dark roasts generally gave higher concentrations.

Both camps are quoting a real result and omitting which variable was held constant. The practical takeaway is that roast is a small effect next to dose, and worth ignoring while you are still weighing by scoop.

What the reference number means

The FDA on how much caffeine is too much cites 400 milligrams a day — about two to three 12-ounce cups of coffee — as an amount not generally associated with negative effects for most healthy adults. It also says plainly that there is wide variation in how sensitive people are and how fast they clear caffeine, and that body weight, medications and medical conditions all change what "too much" means.

So it is a population reference point, not a personal limit. CupTune's caffeine calculator shows it as a line your estimated range may sit below, above or across, and says which of those three it is rather than pretending to know your day.

This is not health advice

CupTune is a brewing tool. It does not know your health, your medication or your sensitivity, its estimate is arithmetic on a wide literature range rather than a measurement of your cup, and nothing here should be used to make a medical decision. If caffeine matters for your health, that is a conversation with a clinician, not with a calculator.