Caffeine Calculator

Created by Bogna Szyk and Łucja Zaborowska, MD, PhD candidate
Reviewed by Steven Wooding
Based on research by
Temple JL, Bernard C, Lipshultz SE, Czachor JD, Westphal JA, Mestre MA. The Safety of Ingested Caffeine: A Comprehensive Review. Frontiers in Psychiatry (May 2017)
Last updated: Sep 25, 2023

This caffeine calculator finds out how much caffeine you had during a day. Thanks to this tool, you will be able to quickly assess if you should stop drinking coffee or you can drink one more cup to regain your energy.

In this article, we will tell you what a lethal dose of caffeine is and how much caffeine you should have a day.

Keep reading to find out, or head to our blood alcohol calculator if you are interested in a similar tool for alcohol.

How to use the caffeine overdose calculator

You can use our calculator to determine the total intake of caffeine from three different sources.

  1. First, choose a caffeine source – for example, cups of tea or espresso shots.

  2. Then, enter how many of these you had during the day.

  3. Repeat the first two steps for every caffeine source.

  4. The caffeine calculator will automatically find your total caffeine intake.

You can choose from the following list of caffeine sources:

  • Cup of tea (190 g): 50 mg per cup
  • Mugs of filter coffee (350 g): 140 mg per mug
  • Mugs of instant coffee (350 g): 100 mg per mug
  • Cans of cola (330 ml): 40 mg per can
  • Energy drinks (250 ml): 80 mg per can
  • Shots of espresso: 45 mg per shot
  • Cups of green tea (190 g): 40 mg per cup

Bored of boring old coffee? Would you like to try something new? Take a look at the instructions featured in our coffee ratio calculator. ☕

Did you know that a cup of cold brew coffee has up to 4.5 times more the amount of caffeine than a regular cup of hot drip coffee? Check out our cold brew ratio calculator to learn more about this.

How much caffeine should I have a day?

The maximum amount of caffeine depends on your age, gender, and health condition. For example, if you often have a high blood pressure (check with the MAP calculator](calc:587)), you should consult your doctor for a recommended daily caffeine intake.

You can use the following values as a rule of thumb:

  • Adults – The maximum daily dose shouldn't exceed 400 mg. It is equivalent to three large mugs of filter coffee – if you drink more than that, it can have a negative influence on your health.

  • Teenagers (aged 13-18) – As the teenagers' bodies are still developing, they should limit their caffeine intake to about 100 mg a day. It corresponds to one large mug of coffee or two shots of espresso.

  • Children (below 13) – Small children should generally avoid caffeine. It is not advisable to provide them with substantial amounts of coffee.

  • Pregnant women – The maximum recommended caffeine limit in case of pregnancy is 200 mg per day.

What is a lethal dose of caffeine?

Don't worry if you discover that your daily caffeine intake exceeds the recommended value. It is extremely unlikely that one or two additional cups of coffee will cause a stroke or another serious health condition.

It is assumed that the lethal dose of caffeine is about 10 grams. That corresponds to about 70 mugs of coffee, 125 energy drinks, or 200 cups of tea. While it is almost impossible to reach that dose with traditional caffeine sources, you should make sure that you keep your caffeine intake at a reasonable level.

Bogna Szyk and Łucja Zaborowska, MD, PhD candidate
I had...
mugs of filter coffee
How many?
I also had...
cups of tea
How many?
And I had...
energy drinks
How many?
Your caffeine intake
I am...
an adult
Max recommended dose
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