โข๏ธHalf-Life Calculator
Solve for initial amount, remaining amount, half-life, or elapsed time.
Runs entirely in your browser. No data is sent to a server.
Free Half-Life Calculator
Working through a radioactive decay or half-life problem? Our free half-life calculator solves for whichever value you're missing โ initial amount, remaining amount, half-life, or elapsed time โ using the standard exponential decay formula. Pick a common isotope like Carbon-14 or Uranium-238 from the preset list to auto-fill its known half-life, or enter your own.
Alongside the answer, you'll see the decay constant, mean lifetime, and percent remaining, plus a decay curve chart plotting the exponential drop-off with your solved point marked. Every step of the calculation, including any logarithms needed, is shown clearly.
Ideal for chemistry, physics, or nuclear science coursework, it runs entirely in your browser. No sign-up, no downloads, no limits. See the About page or the FAQ for more.