Compound Interest Calculator
Calculate how your savings or investments grow over time with the power of compound interest. This essential calculator shows how reinvested earnings generate exponential growth — ideal for deposit planning, retirement goals, or long-term investing. You can include regular contributions and see detailed growth by period.
Compound Growth Calculator with Contributions
Compound Interest Formula with Regular Deposits
Where:
- $$A$$ = future value of the investment
- $$P$$ = initial principal
- $$r$$ = interest rate per period (as decimal)
- $$n$$ = total number of periods
- $$PMT$$ = regular contribution per period
Compound Interest – Calculation Example
Suppose you invest $5,000 at 6% annual interest compounded yearly, with monthly contributions of $200 for 10 years:
- $$P$$ = 5000
- $$r$$ = 0.06 / 12 = 0.005
- $$n$$ = 12 × 10 = 120
- $$PMT$$ = 200
- $$A \approx 5000 \cdot (1 + 0.005)^{120} + \frac{200 \cdot \left( (1 + 0.005)^{120} – 1 \right)}{0.005}$$
- $$A \approx \$34{,}719.67$$
Compound interest means “interest on interest” — each period’s earnings are reinvested to generate even more profit. This calculator handles:
- One-time deposits
- Regular contributions (monthly, quarterly, yearly)
- Any interest rate and compounding frequency
It’s ideal for calculating bank deposits, long-term savings, retirement funds, education investments, and more. The growth curve is exponential — even small contributions can lead to impressive results over time.
Use this calculator to visualize future gains and fine-tune your investment strategy.