Tools / Daily caffeine calculator

Tea, coffee and labeled drinks

Daily caffeine calculator

Add everything you drink, include the time, and get a transparent low-to-high estimate with a shareable URL.

How much caffeine am I drinking?

Select each beverage, set the serving count, and the calculator sums its caffeine range. Use the product label when available because brand, size, and preparation can differ substantially.

FDA-based beverage presetsSources reviewed July 24, 2026Evidence policy

Build your day

Add each drink once, then set its number of servings. Replace a preset with label values whenever you have them.

Drink 1

FDA category value; a particular tea and preparation can differ. Source

Drink 2

Regular brewed, non-specialty coffee. Source

Estimated daily total: 150–284 mg
2 total servings0–0 mg logged at or after 2:00 PM

For visual context, the bar compares the high estimate with the FDA’s 400 mg/day reference for most adults. It is not a personal limit.

How the result is calculated

Daily caffeine range formula

daily low = Σ(servings × low mg per serving); daily high = Σ(servings × high mg per serving)

Each drink contributes a low and high estimate. The tool adds those endpoints without pretending the midpoint is a measured intake. A product label should replace a generic preset when it states caffeine for the exact serving consumed.

Worked example: green tea and brewed coffee

  1. One FDA-category green tea preset contributes 37 mg.
  2. One 12 fl oz brewed coffee contributes an FDA range of 113–247 mg.
  3. Daily low: 37 + 113 = 150 mg. Daily high: 37 + 247 = 284 mg.
  4. The range describes uncertainty in the selected values; it is not a personalized safe limit.

From result to decision

How to interpret the result

Result patterns, what they mean, and the next useful action
ResultWhat it meansWhat to do next
A narrow rangeThe selected products or labels provide relatively specific caffeine values.Confirm serving size and count repeat servings.
A wide rangeGeneric categories or variable preparation create substantial uncertainty.Replace presets with exact label values or measured product data when available.
Late-day caffeine loggedTiming does not change total milligrams but may matter to a person’s routine and sleep discussion.Use the time field to identify which drinks occur later in the day.

Inputs explained

Variables and definitions

Serving
The preset’s stated volume or the portion described on a product label.
Servings
How many of that exact portion are consumed in the day; half-servings are allowed.
Low and high caffeine
The range in milligrams for one serving before multiplying by count.
Time
Optional time consumed, used to separate entries logged at or after 2:00 PM; it does not alter milligrams.
400 mg reference
FDA general context for most adults, not an individual prescription or target.

Exceptions that matter

Edge cases and common mistakes

  • Pregnancy, breastfeeding, childhood, medicines, heart rhythm concerns, anxiety, sleep disorders, and individual sensitivity require more specific guidance.
  • Matcha, yerba mate, espresso, bottled tea, supplements, chocolate, and medicines vary by product; use the label or a custom entry.
  • Decaffeinated products can still contain caffeine.
  • Tea caffeine varies with leaf material, dose, water, time, temperature, serving volume, and repeated infusions.

Direct answers

Frequently asked questions

How much caffeine is in tea?

It varies widely. The cited brewed-tea study observed 14–61 mg in its 6- or 8-ounce servings, while exact products and preparations can fall elsewhere.

Is 400 mg of caffeine safe for everyone?

No. The FDA uses 400 mg/day as general context for most adults, but sensitivity and individual circumstances can require different advice.

Does green tea always have less caffeine than black tea?

Not necessarily for a particular cup. Leaf, dose, water, time, temperature, and serving size can outweigh the category label.

Does decaf mean caffeine-free?

No. The FDA notes that decaffeinated coffee and tea can still contain caffeine.

Should I use the label or the preset?

Use the exact product label when it provides caffeine for the serving you consumed; generic presets are fallback estimates.

Trace the method

Sources and calculation basis

Method and source review updated .

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