Calculate remaining amount after radioactive decay.
To calculate radioactive decay:
The calculator shows the remaining amount, number of half-lives elapsed, and the percentage that has decayed.
Radioactive decay formula:
Remaining = Initial × (0.5)^(Elapsed Time ÷ Half-Life)
Elapsed Time ÷ Half-LifeInitial − Remaining(Decayed ÷ Initial) × 100Example: 1000 g of Carbon-14 (half-life = 5,730 years) after 11,460 years.
11,460 ÷ 5,730 = 21000 × (0.5)² = 250 g1000 − 250 = 750 g (75%)Half-life is the time required for half of a radioactive substance to decay. After one half-life, 50% remains. After two, 25%. After three, 12.5%. The process is exponential — a substance never fully reaches zero.
No. The half-life concept applies to any exponential decay process. It's used in pharmacology (drug elimination from the body), chemistry (reaction rates), biology (protein degradation), and even finance (depreciation models).