Half-Life Calculator
Calculate how much of a substance remains after decay.
Result
Results are estimates for general information only and are not professional advice.
Half-life decay
Half-life is the time for a quantity to reduce to half its value. Using N = N₀ × (½)^(t/half-life), this calculator finds how much remains after a given time — useful in physics, chemistry and medicine.
Frequently Asked Questions
What is the Half-Life Calculator?
Calculate how much of a substance remains after decay. It runs instantly in your browser and is completely free to use.
What do I need to enter to use the Half-Life Calculator?
The Half-Life Calculator asks for the following values (3): Initial quantity, Half-life, Elapsed time. Fill them in and the result appears immediately — the calculation runs on your own device, so nothing you type is sent to a server.
How accurate is the Half-Life Calculator?
The Half-Life Calculator uses standard, widely-accepted formulas, so its figures are reliable estimates for everyday planning. They are not a substitute for advice from a qualified professional.
Is the Half-Life Calculator free, and do I need an account?
Yes. The Half-Life Calculator — and every other calculator on Calculatis — is completely free, with no registration, no download and no limit on how often you use it.