Exponential Decay Calculator

Calculate exponential decay over time. Model radioactive decay, depreciation, or cooling.

%

Remaining

590.49

Lost409.51
Pct Remaining59.05 %
Half Life6.58

Exponential Decay

Formula

Remaining = Initial × (1 - r)^t

where r is the decay rate per period and t is the number of periods.

Half-Life

The time for the quantity to reduce to half:

t½ = ln(0.5) / ln(1 - r)

Example Calculation

1000 decaying at 10% per period for 5 periods.

  1. 01Remaining = 1000 × (0.90)^5
  2. 02= 1000 × 0.59049
  3. 03= 590.49
  4. 04Amount lost = 409.51
  5. 05Half-life = ln(0.5)/ln(0.90) ≈ 6.58 periods

Frequently Asked Questions

Learn More

How to Calculate Percentages - Complete Guide

Learn how to calculate percentages step by step. Covers finding a percentage of a number, percentage change, reverse percentages, and real-world applications.

Related Calculators