How Much Caffeine Is in Cold Brew?

How to use this cold brew caffeine calculator

1. Enter your batch. How much ground coffee went in, and how much water. Grams and millilitres are the most accurate, but tablespoons, scoops, ounces, cups and litres all work — the tool converts.
2. Set the steep. Drag the slider to the hours you actually left it, and say whether it sat on the counter or in the fridge. The tool shows what percentage of the available caffeine that steep extracted.
3. Pick your beans. Roast level and species both move the number — and not in the direction most people assume.
4. Say how you pour it. Straight over ice, or cut with water or milk. This is the single biggest lever on what lands in the glass, and it's the reason published numbers disagree so wildly.
5. Choose your glass. The result updates live — there's no Calculate button. Copy it, share a link that reopens your exact brew, or download a brew card PDF.

Why this calculator is different

Search this question and you get static numbers with no working shown. This one is built to answer it for your jar:

• The math comes from a peer-reviewed study, and we show it. The yield model is derived from Fuller & Rao (2017) in Scientific Reports, who brewed 35 g of coffee in 350 mL of water and measured caffeine by HPLC over 24 hours. Their numbers are printed below, and a fixture test reproduces their published table on every single build, so this page cannot quietly drift away from the source.
• It doesn't ask for your grind size — because grind size doesn't matter here. That same study found grind had no statistically significant effect on cold brew caffeine. Several of the top-ranking pages on this topic tell you a finer grind extracts more caffeine. For an 8-to-24-hour immersion, the published data says otherwise, and asking you for a number that doesn't change the answer would only add false precision.
• It reconciles the numbers you've read elsewhere. The result sits next to a Starbucks cold brew, a Dunkin' cold brew, a mug of drip and a double espresso, so you can see where your jar falls instead of guessing.
• It treats this as a dose, not trivia. Cold brew is the easiest way in coffee to drink far more caffeine than you meant to. The result is measured against the FDA's 400 mg daily guidance, with a meter and a plain-language warning when one glass clears it.
• It's shareable, printable and embeddable — a link that reopens your exact brew, a branded PDF brew card, and a free embed with the sources cited below.

How it works (the math)

The honest unit here isn't "milligrams per cup" — it's milligrams of caffeine per gram of dry coffee, because that's the part that doesn't change when you move to a bigger jar. Everything else is bookkeeping:

mg_per_gram = roast_yield x species_factor x extraction(t)
extraction(t) = (1 - e^(-t/tau)) / (1 - e^(-24/tau_room))

total_mg    = coffee_g x mg_per_gram
yield_mL    = water_mL - (coffee_g x 2)     // grounds keep ~2 g each
finished_mL = yield_mL x (1 + dilution)
mg_in_glass = total_mg / finished_mL x glass_mL

The roast yields are measured, not guessed. Fuller & Rao reported 1,180 and 1,230 mg/L for medium-roast coffee at 24 hours (medium and coarse grind), and 1,080 and 990 mg/L for dark. At their 35 g : 350 mL ratio that works out to 12.05 mg of caffeine per gram of coffee for a medium roast and 10.35 for a dark one. Yes — dark roast extracts less, which is the opposite of what "dark roast is stronger" suggests.

The extraction curve is fitted to the study's own data. They sampled at 400 minutes and again at 1,440 (24 hours), and across all four samples the 400-minute figure averaged 91.4% of the 24-hour one. A time constant of 2.7 hours reproduces that to within a fraction of a percent. Practically: most of the caffeine is out in the first 3 hours, you're at roughly 95% by 8 hours, and past about 18 hours you are steeping for flavour, not for caffeine.

Species scales the whole thing. Arabica is roughly 1.2% caffeine by dry weight and robusta roughly 2.2%, so a robusta-heavy blend carries about 1.8 times the caffeine of the same weight of arabica. The study used arabica, so arabica is the baseline.

Limitations, stated plainly. Light roast was not in the Fuller & Rao dataset — it's modelled 3% above medium, extrapolated from the medium-over-dark trend and the mass a bean loses in the roaster. The fridge setting slows the extraction curve rather than lowering its ceiling, which matches the chemistry but wasn't directly measured (the study ran at room temperature). And real beans vary by origin and harvest. This is a well-sourced estimate, not a lab assay of your particular jar.

Three worked examples

The standard home jar, poured straight

100 g of medium-roast arabica in 1 litre of water — a 1:10 ratio — steeped 16 hours at room temperature. The grounds drink about 200 mL, so you pour off roughly 800 mL holding about 1,200 mg of caffeine. A 16 oz glass of that, undiluted, is around 710 mg. That is not a typo, and it is not a Starbucks: it's about three and a half times a Starbucks cold brew, and comfortably past the FDA's guidance for an entire day — in one glass, before breakfast.

The same jar, diluted like a café does

Take that identical batch and cut it roughly one part brew to two and a half parts water or milk, which is broadly how a coffee shop serves concentrate. The same 16 oz glass now lands at about 200 mg — which is exactly the figure Healthline and most of the internet quote for "a cold brew." Nothing about the coffee changed. Only the pour did. That one comparison explains most of the contradictory numbers you'll find on this topic.

A deliberately gentle batch

28 g in 800 mL, steeped 12 hours, served straight in an 8 oz glass, comes out around 106 mg — a little more than a mug of drip coffee, and about three glasses from the daily limit. If you like cold brew daily rather than occasionally, this is the shape of batch to aim for. Our cold brew ratio calculator will size the jar; this one tells you what it does to you.

Frequently asked questions

How much caffeine is in cold brew?

A 16 oz ready-to-drink cold brew averages about 200 mg — a Starbucks is 205 mg and a Dunkin' is 260 mg. But a homemade 1:10 batch poured straight over ice can be 600 to 900 mg in the same glass, because café cold brew is brewed as a concentrate and diluted before it reaches you, and a home jar usually isn't. The single most useful thing you can know about cold brew caffeine is whether what you're drinking has been cut.

Does cold brew have more caffeine than regular coffee?

Per glass, usually yes — a 16 oz cold brew at ~200 mg beats an 8 oz mug of drip at ~95 mg, mostly because it's twice the volume and brewed with more coffee. Per gram of coffee, cold and hot brewing extract remarkably similar amounts of caffeine; Fuller & Rao found cold brew slightly higher for coarse grinds and statistically indistinguishable for medium ones. The reputation cold brew has for being strong is mostly a ratio-and-serving-size story, not a chemistry one.

Does steeping longer make cold brew more caffeinated?

Up to a point, and that point comes sooner than most recipes suggest. Caffeine extraction is fast at first and then flattens: roughly two-thirds is out at 3 hours, about 95% by 8, and essentially all of it by 18 to 24. Going from a 16-hour steep to a 24-hour one adds only a few percent. Longer steeps still change the flavour — more body, more bitterness, more woody notes — but they are not a meaningful caffeine lever. If you want a stronger cold brew, use more coffee, not more time.

Does dark roast cold brew have more caffeine?

No — it has slightly less. This is the most stubborn myth in coffee. Caffeine is heat-stable, so roasting doesn't burn it away, but Fuller & Rao measured medium roasts at about 1,205 mg/L against dark roasts at 1,035 under identical conditions, roughly 14% lower. Dark roast tastes bolder and smokier, and people read that as caffeine. If you're chasing milligrams, a medium roast measured by weight gives you more. Have a look at our best coffee beans picks for grinds that suit a long cold steep.

How much caffeine is in cold brew concentrate?

A lot, and it's the number people most often get wrong. Concentrate is typically brewed at 1:4 to 1:5, so the liquid coming off the grounds can carry 2 to 3 mg of caffeine per millilitre — meaning a single 12 oz glass of undiluted concentrate can exceed 800 mg, twice the FDA's daily guidance. Concentrate is meant to be cut roughly 1:1 or more before drinking. Set the dilution control in the calculator to match how you actually pour it, and the result will follow.

Is cold brew too much caffeine for one day?

It can be, easily. The FDA points to 400 mg a day for healthy adults, and 200 mg is the usual guidance in pregnancy. A café cold brew uses about half of an adult day's allowance in one cup; a strong homemade one can use all of it and then some. That doesn't make cold brew a problem — it makes it worth measuring. Add up everything you drink with our caffeine intake calculator, and if it's late in the day, our caffeine half-life calculator will tell you when it clears.

Related tools

• Cold Brew Coffee Ratio Calculator — size the jar first: coffee, water, dilution and how many servings it makes. This tool then tells you what's in each one.
• Caffeine Intake Calculator — add a glass of your cold brew to everything else you drank today and check it against a safe daily limit for your weight and life stage.
• Caffeine Half-Life Calculator — a 700 mg cold brew is still working on you many hours later. See exactly when it drops below a sleep-safe level.
• Coffee to Water Ratio Calculator — the same ratio thinking for every hot brewing method.
• Browse all free coffee tools by Clara →

Gear that makes the number repeatable

A caffeine estimate is only as good as the dose it starts from, and "a couple of scoops" isn't a dose. Three things turn cold brew from a guess into something you can actually control:

• A scale. Grams are the only unit that behaves — a scoop of light roast and a scoop of dark are different amounts of coffee. A 0.1 g scale makes every batch reproducible.
• A brewer sized to your habit. A quart jar brews a couple of days; a half-gallon kit brews the week. Picking the right one is quietly the best caffeine control there is — see our best cold brew coffee makers guide.
• Beans that hold up diluted. If you're cutting concentrate with water or milk, you want a bean with enough character to survive it. Our best coffee beans and best coffee grinders roundups cover both halves of that.

Sources & methodology

• Fuller, M. & Rao, N.Z. (2017) — "The Effect of Time, Roasting Temperature, and Grind Size on Caffeine and Chlorogenic Acid Concentrations in Cold Brew Coffee", Scientific Reports 7:17979 — the primary source for every yield figure and the extraction curve. 35.0 g of coffee in 350 mL of water at 21–25 °C, sampled to 24 hours, n = 6.
• Healthline — How Much Caffeine Is in Cold Brew Coffee? — the commercial comparison values (Starbucks 205 mg and Dunkin' 260 mg per 16 oz, citing each chain's published nutrition data).
• FDA — Spilling the Beans: How Much Caffeine Is Too Much — the 400 mg daily reference for healthy adults.
• EFSA — Scientific Opinion on the Safety of Caffeine (2015) — daily and single-dose safety context, including the 200 mg pregnancy guidance.

Yields at equilibrium: 12.05 mg caffeine per gram of coffee (medium roast) and 10.35 (dark), converted from Fuller & Rao's published concentrations at their stated ratio. Light roast is extrapolated at +3% over medium and is flagged as such in the tool. Grind size is not modelled, because that study found no significant grind effect on cold brew caffeine. Extraction follows (1 − e^(−t/τ)) with τ = 2.7 h at room temperature, fitted to the study's own 400-minute and 24-hour samples; the fridge setting uses τ = 4.6 h as an approximation. Species scaling uses arabica ~1.2% and robusta ~2.2% caffeine by dry weight. Grounds are assumed to retain 2 g of liquid per gram of dry coffee, matching our cold brew ratio calculator. Thirteen fixtures, six invariants and seven edge cases run on every build, three of which reproduce the source study's published table directly. Educational estimate only — not medical advice. Reviewed by Clara Bennett, CQI Q Grader. About Clara · Last reviewed August 17, 2026.

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