CAFFEINE CALC
Your blood caffeine level today?
Is Your Caffeine Intake Safe?
Everybody loves coffee, but caffeine stays in your system longer than you think. The 'Half-Life' of caffeine is about 5 hours on average, meaning half of the caffeine you consumed is still circulating in your blood 5 hours after your last sip.
Excessive caffeine can lead to insomnia, anxiety, and increased heart rate. This calculator estimates your current blood caffeine level based on consumption time and predicts exactly when you will be 'clean' enough to sleep soundly.
For practical sleep planning, compare your usual intake schedule with an earlier cutoff schedule. Reviewing both scenarios helps you reduce sleep disruption without overcorrecting your daytime caffeine routine.
Frequently Asked Questions
What is Caffeine Half-Life?
It is the time required for your body to eliminate 50% of the caffeine. It varies from 3 to 7 hours depending on genetics, age, and liver health. We use a standard 5-hour model.
How much caffeine is safe?
According to the FDA, up to 400mg per day (about 4 cups of coffee) is considered safe for most healthy adults. However, sensitivity varies widely.
Does drinking water help flush out caffeine?
Not significantly. Caffeine is metabolized by liver enzymes (CYP1A2), not just filtered by kidneys. Staying hydrated helps with side effects like jitters, but it won't drastically speed up the elimination process.