How do I calculate half-life? Enter your numbers above and the result updates instantly. For example: Initial quantity: 100 · Half-life: 5,730 · Time elapsed: 10,000 → Remaining quantity: 29.8292.
Is this Half-Life Calculator free? Yes — completely free with no sign-up or paywall. It runs entirely in your browser and keeps working offline; the numbers you enter never leave your device.
How accurate is it? It uses the standard published formula for half-life. Results are estimates for planning — not financial, tax, medical, engineering, or legal advice.