Compound interest calculator - deposit growth
Calculate the future value of a deposit or investment with compound interest and monthly contributions.
Calculations are based on Estonia's tax rates in force for 2026. Results are informational.
Last updated: 2026-06-03
What is compound interest?
Compound interest earns interest on both the initial amount and the interest already accrued, so money grows exponentially. Future value = principal × (1 + r)^n plus the monthly contributions.
How it is calculated
Formula
FV = P × (1 + r)ⁿ + PMT × ((1 + r)ⁿ − 1) ÷ r, where r is the monthly rate, n the number of months and PMT the monthly contribution. Total interest = FV − contributions.
Example
Starting capital 1000 €, 100 €/month, 6% per year, 10 years → ≈ 18,245 €, of which interest ≈ 4245 €.
Frequently asked questions
What is compound interest?+
Compound interest is earned on both the initial capital and the interest already accrued, so the balance grows at an accelerating pace.
How do monthly contributions affect the result?+
Regular contributions raise the final amount significantly, since they too earn interest over the whole period.