Exponential Decay Calculator
Calculate the final value of a quantity declining at a fixed percentage rate over a number of periods.
- Free to use
- Accurate results
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- Works on all devices
Enter an initial value, decay rate, and number of periods to find the final value.
Your result
590.49
Final value
Total decline409.51
AI explanation
Formula
Final value = initial value × (1 − decay rate)^periodsWorked example
1000 decaying at 10% for 5 periods
| Field | Value |
|---|---|
| Initial value | 1000 |
| Decay rate per period (%) | 10 |
| Number of periods | 5 |
| Final value | 590.49 |
| Total decline | 409.51 |
Assumptions
- Uses discrete-period decay — the decay rate applies once per period, not continuously.
Frequently asked questions
What is exponential decay?
Decline where the decrease in each period is proportional to the current value — the quantity shrinks by the same percentage each period, so it never quite reaches zero.
What real-world quantities decay exponentially?
Radioactive decay, drug concentration in the bloodstream, and depreciating asset value (under a declining-balance method) are common examples.
How is this related to half-life?
Half-life describes a specific case of exponential decay where the decay rate is defined by how long it takes to lose half the quantity — see the Half-Life Calculator for that framing.