A walkthrough, end to end.
- 1
Enter the initial quantity, the per-period growth rate (as %), and the number of periods.
- 2
The calculator returns the final amount, total growth, and the equivalent decay form if rate is negative.
- 3
Switch to continuous growth (e^(rt)) for instantaneous compounding.
Exponential growth
Discrete: N(t) = N₀ × (1 + r)ᵗ. Continuous: N(t) = N₀ × e^(rt). Negative r yields exponential decay.
What you can do with this.
Population growth
Project a city's population at 1.2% annual growth over 30 years.
Bacterial growth
Cells doubling every 20 minutes for 4 hours.
Viral spread
Estimate cases at a constant reproduction rate.
Investment growth
Like compound interest with a single rate.
Subscriber growth
Project audience size at a steady weekly rate.
Inflation projection
How prices change at a fixed annual inflation rate.
Decay (negative rate)
Model decline at a constant percentage per period.
Exponential 2026 — what's current
Foundational; calculator wins for instant projections.
Frequently asked.
Discrete uses (1+r)ᵗ for distinct periods. Continuous uses e^(rt) for instantaneous compounding.
Yes — the calculator handles decay automatically.
No. All math runs in your browser.
Whatever you pick — just keep the rate per period consistent.