Physics Tools
Free physics calculators — radioactive half-life and decay with isotope presets, with lens, wave, Doppler, orbit and relativity tools queued next.
Physics tools
Why These Tools
Carbon dating, hospital tracer doses and the age of rocks all rest on one equation: after every half-life, half of what was there is gone. Half-Life Calculator solves it for whichever quantity is missing, whether that is the time elapsed, the half-life itself or the amount left, and draws the decay curve next to the answer. Eight isotope presets fill in published half-lives, from 6.01 hours for technetium-99m to 4.468 billion years for uranium-238.
More of a physics course will follow. Lens and mirror equations, Snell's law, Doppler shifts, orbital periods and time dilation are next, each showing its working rather than a bare number.