Half-Life Calculator | Solve Exponential Decay & Half-Life
This free half life calculator solves radioactive and drug decay equations. Calculate remaining amount, initial quantity, half-life, or elapsed time with step-by-step formulas and curves.
Known Variables
Solved decay value
25units
Decayed Quantity: 75%Remaining: 25.00%
Half-Lives Elapsed2.00
Decay Constant (λ)8.6643e-2
Elapsed Time (t)16.0 days
Step-by-Step Exponential Decay Calculations
1
Remaining Amount Formula:
N(t) = N₀ × (0.5)^(t / t_½)
100 × (0.5)^(16 days / 8 days) = 25.0000
Five-Cycle Decay Schedule Ledger
| Cycles | Time Elapsed | Remaining | % Left | Decayed |
|---|---|---|---|---|
| 0 t½ | 0.00 days | 100 | 100% | 0 |
| 1 t½ | 8.00 days | 50 | 50% | 50 |
| 2 t½ | 16.00 days | 25 | 25% | 75 |
| 3 t½ | 24.00 days | 12.5 | 12.5% | 87.5 |
| 4 t½ | 32.00 days | 6.25 | 6.25% | 93.75 |
| 5 t½ | 40.00 days | 3.125 | 3.13% | 96.875 |