Drug Half-Life Calculator
Calculate drug elimination kinetics including remaining concentration, time to target levels, and steady state timing based on half-life.
Drug Parameters
units
Peak or starting drug level
units
Level you want to reach (optional)
Remaining Concentration
6.25 units
After 4.00 half-lives
📉% Remaining
6.3%
🗑️% Eliminated
93.8%
📊Elimination Rate (k)
0.1155 /hr
⏱️Number of Half-Lives
4.00
Time Estimates
Time to target (10 units): 19.9 hours
Time to 90% elimination: 19.9 hours
Time to 99% elimination: 39.9 hours
Steady state (5 half-lives): 30.0 hours
Key Points
After 4-5 half-lives, drug reaches steady state or is essentially eliminated
Each half-life reduces concentration by 50%
Elimination Reference
| Half-Lives | % Remaining | % Eliminated |
|---|---|---|
| 1 | 50.00% | 50.00% |
| 2 | 25.00% | 75.00% |
| 3 | 12.50% | 87.50% |
| 4 | 6.25% | 93.75% |
| 5 | 3.13% | 96.88% |
| 6 | 1.56% | 98.44% |
| 7 | 0.78% | 99.22% |