Caffeine in your body
Enter your numbers — the results update instantly.
Remaining114.87 mg
Until below 25 mg11 h
Worked example
Given: Caffeine taken (mg) = 200; Hours ago = 4; Half-life (hours) = 5
Result: Remaining = 114.87 mg; Until below 25 mg = 11 h
How it is calculated
1. Enter the values you know. 2. The calculator converts them to base units and applies the formula. 3. The result is shown in the unit you choose.
Frequently asked questions
How do I calculate it?
Given: Caffeine taken (mg) = 200; Hours ago = 4; Half-life (hours) = 5. Result: Remaining = 114.87 mg; Until below 25 mg = 11 h.
Is the calculator free and private?
Yes. It is free, needs no sign-up and runs in your browser — the numbers you type stay on your device.