How much caffeine is safe per day?

The FDA recommends up to 400mg of caffeine per day for healthy adults. That is roughly 4 cups of coffee. Pregnant women should limit intake to 200mg per day.

How long does caffeine stay in your system?

Caffeine has a half-life of about 5 hours. This means half of the caffeine consumed is still in your system after 5 hours. It can take 10–12 hours to clear most of the caffeine from your body.

How much caffeine is in a cup of coffee?

An 8oz brewed coffee contains approximately 95mg of caffeine. An espresso shot has about 63mg. Amounts vary based on roast, brewing method, and brand.

Does caffeine affect sleep?

Yes. Caffeine blocks adenosine receptors that promote sleep. Having more than 50–100mg of caffeine in your system at bedtime can delay sleep onset and reduce sleep quality.

What is the caffeine content of energy drinks?

Red Bull (8.4oz) contains 80mg, while a 16oz energy drink typically has 160mg. Always check the label as brands vary significantly.

Caffeine Intake Calculator

Calculate your daily caffeine intake from coffee, tea, and energy drinks. Check against the 400mg FDA limit and see how caffeine affects your sleep.

Drink Type ?

Number of Drinks ?

Total Caffeine (mg)

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Safety Status —

Half-Life Estimate —

Extended More scenarios, charts & detailed breakdown ▾

Drink 1 Type

Drink 1 Count

Drink 2 Type

Drink 2 Count

Total Daily Caffeine

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Over FDA Limit? —

Remaining Budget —

Professional Full parameters & maximum detail ▾

Total Daily Caffeine (mg)

Last Caffeine Hour (24hr) ?

:00

Bedtime Hour (24hr)

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Pregnancy Mode

Safety

Safe Intake Status —

Limit (Pregnancy) —

Sleep Impact

Caffeine Remaining at Bedtime —

Sleep Impact —

Clearance

Hours to Full Clearance (~10mg) —

How to Use This Calculator

Select your drink type from the dropdown (coffee, espresso, tea, energy drink, etc.).
Enter the number of drinks you have consumed or plan to consume today.
View your total caffeine intake and whether it is within the FDA safe limit of 400mg.
Use the Daily Intake tab to combine multiple drink types.
Use the Metabolism tab to see how much caffeine is still in your system hours after consumption.

Formula

Total Caffeine = mg per drink × number of drinks

Caffeine Remaining = Initial × (0.5)^(hours / 5)

Half-life of caffeine = ~5 hours for most adults

Example

Example: 2 cups of coffee + 1 Red Bull = 190mg + 80mg = 270mg total. Well within the 400mg FDA limit. If consumed at 2 PM and bedtime is 10 PM (8 hours later), ~52mg remains at bedtime.

Frequently Asked Questions

The FDA recommends up to 400mg of caffeine per day for healthy adults. That is roughly 4 cups of coffee. Pregnant women should limit intake to 200mg per day.
Caffeine has a half-life of about 5 hours. This means half of the caffeine consumed is still in your system after 5 hours. It can take 10–12 hours to clear most of the caffeine from your body.
An 8oz brewed coffee contains approximately 95mg of caffeine. An espresso shot has about 63mg. Amounts vary based on roast, brewing method, and brand.
Yes. Caffeine blocks adenosine receptors that promote sleep. Having more than 50–100mg of caffeine in your system at bedtime can delay sleep onset and reduce sleep quality.
Red Bull (8.4oz) contains 80mg, while a 16oz energy drink typically has 160mg. Always check the label as brands vary significantly.