- Final balance
- €332,567.76
- Interest / growth
- €172,567.76
Savings and investment growth planner
Compound Interest Calculator
Calculate how your savings or investments can grow with compound interest, recurring contributions and different return scenarios.
Year-by-year projectionRuns in your browserPDF summary and print
Investment and contributions
Enter the amount invested now and any regular additions.
Return and time
Set an illustrative annual return and how often growth compounds.
The return rate is an assumption for illustration. It is not guaranteed and does not include fees or taxes.
Inflation adjustment
Keep the nominal projection and optionally estimate its value in today's money.
Projected final balance
€462,290.03
After 25 years at an illustrative 7% annual return.
Total Contributions€160,000.00
Interest / Growth€302,290.03
Growth Multiple2.89×of contributions
Total Return188.93%relative to contributions
Contributions vs interest / growth35% / 65%
Contributed€160,000.00Interest / growth€302,290.03
Investment Growth Over Time
See the projected balance separate from the money contributed.
Total balanceContributions
Move over the chart to inspect a year.
Compare Return Scenarios
Edit conservative, base and optimistic assumptions without changing the main projection.
- Final balance
- €462,290.03
- Interest / growth
- €302,290.03
- Final balance
- €654,645.11
- Interest / growth
- €494,645.11
Year-by-Year Growth
Annual opening balance, contributions, growth and closing balance.
| Year | Starting balance | Contributions | Interest / growth | Ending balance |
|---|---|---|---|---|
| 1 | €10,000.00 | €6,000.00 | €919.19 | €16,919.19 |
| 2 | €16,919.19 | €6,000.00 | €1,419.38 | €24,338.58 |
| 3 | €24,338.58 | €6,000.00 | €1,955.73 | €32,294.31 |
| 4 | €32,294.31 | €6,000.00 | €2,530.85 | €40,825.16 |
| 5 | €40,825.16 | €6,000.00 | €3,147.55 | €49,972.70 |
| 6 | €49,972.70 | €6,000.00 | €3,808.82 | €59,781.53 |
| 7 | €59,781.53 | €6,000.00 | €4,517.90 | €70,299.43 |
| 8 | €70,299.43 | €6,000.00 | €5,278.24 | €81,577.68 |
| 9 | €81,577.68 | €6,000.00 | €6,093.55 | €93,671.22 |
| 10 | €93,671.22 | €6,000.00 | €6,967.79 | €106,639.02 |
| 11 | €106,639.02 | €6,000.00 | €7,905.24 | €120,544.25 |
| 12 | €120,544.25 | €6,000.00 | €8,910.45 | €135,454.70 |
| 13 | €135,454.70 | €6,000.00 | €9,988.32 | €151,443.02 |
| 14 | €151,443.02 | €6,000.00 | €11,144.12 | €168,587.14 |
| 15 | €168,587.14 | €6,000.00 | €12,383.47 | €186,970.62 |
| 16 | €186,970.62 | €6,000.00 | €13,712.41 | €206,683.03 |
| 17 | €206,683.03 | €6,000.00 | €15,137.43 | €227,820.45 |
| 18 | €227,820.45 | €6,000.00 | €16,665.45 | €250,485.91 |
| 19 | €250,485.91 | €6,000.00 | €18,303.94 | €274,789.85 |
| 20 | €274,789.85 | €6,000.00 | €20,060.87 | €300,850.72 |
Free · No signup · Calculations run in your browser. This calculator provides illustrative estimates only. Investment returns are not guaranteed, and actual results may differ due to market performance, fees, taxes and other factors.
Plan with transparent assumptions
Compound Interest Calculator
Use this free calculator to model a starting balance, recurring deposits and an illustrative annual return. It separates the money you contribute from projected interest or investment growth, then presents the result as a chart, editable scenarios and a year-by-year table.
1. Enter your plan
Add a starting amount, regular contribution, expected return and investment period.
2. Compare outcomes
Review contributions, growth, inflation-adjusted value and three editable return scenarios.
3. Keep the projection
Inspect every year, print a clean summary or download a detailed PDF.
What Is Compound Interest?
Compound interest means earning interest or investment growth not only on the original amount, but also on growth credited in earlier periods. Unlike simple interest, the calculation is repeatedly applied to a changing balance.
Why Compound Interest Becomes Powerful Over Time
Time gives reinvested growth more opportunities to build on itself. The final outcome also depends on the return assumption, how regularly money is added and how long each contribution remains invested. Higher projections are not guarantees.
How Regular Contributions Affect Growth
Monthly, quarterly or yearly additions increase total contributions and place more money into the projection. An optional annual increase can model contributions rising with income—for example, a €500 monthly contribution becomes €515 in year two after a 3% increase.
Compounding Frequency
Daily, monthly, quarterly, semi-annual and annual compounding divide the entered annual rate across different numbers of crediting periods. More frequent compounding can produce a slightly larger result when the same nominal annual rate is used.
Beginning vs End of Period Contributions
A beginning-of-period contribution is added before that period's interest is calculated. It therefore earns growth for one additional period compared with an otherwise identical end-of-period contribution.
Inflation and Real Value
A nominal future balance shows the projected amount of money. Its purchasing power may be lower. When enabled, the calculator also discounts the final balance using your inflation assumption to estimate its value in today's money.
Compound Interest Example
Starting with €10,000, adding €500 at the end of every month and modelling a 7% annual return compounded monthly for 25 years produces an illustrative final balance of €462,290.03. Total contributions are €160,000.00, while projected interest or growth is €302,290.03. These values are generated by the same calculation engine used above.
Compound Interest Calculator FAQ
What is compound interest?
Compound interest is growth calculated on both the original amount and growth already credited. Reinvesting previous returns allows the balance to build on itself over time.
How is compound interest calculated?
The calculator applies the selected annual rate at the chosen compounding frequency, adds recurring contributions at the beginning or end of their periods, and repeats the process across the selected term.
What is the difference between simple and compound interest?
Simple interest is calculated only on the original principal. Compound interest is calculated on the changing balance, including previously credited interest or growth.
How often should interest compound?
The correct frequency depends on the account or investment being modelled. More frequent compounding can produce a slightly higher balance when the stated annual rate and all other assumptions are unchanged.
Does monthly compounding earn more than annual compounding?
Usually yes when the same nominal annual rate is divided and credited more frequently. The difference depends on the rate, term and timing of cash flows.
How do regular contributions affect compound growth?
Regular contributions increase the amount available to grow. Contributions made earlier generally have more time to compound, while annual contribution increases model savings that rise over time.
What does contribution timing mean?
End-of-period contributions are added after that period's growth is credited. Beginning-of-period contributions are added first and therefore participate in one additional period of growth.
How does inflation affect future savings?
Inflation can reduce future purchasing power. The optional real-value estimate discounts the nominal final balance by the entered inflation rate without replacing the nominal result.
Can I compare different rates of return?
Yes. The scenario section calculates conservative, base and optimistic projections from three editable annual rates using the same contribution and timing assumptions.
Is the Compound Interest Calculator free?
Yes. It is free to use and does not require an account or subscription.
Does CalcsBay store my data?
The calculation runs locally in your browser. Ordinary calculator inputs are not sent to a CalcsBay calculation service or saved to an account.
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Disclaimer: This calculator provides illustrative estimates only. Investment returns are not guaranteed, and actual results may differ due to market performance, fees, taxes and other factors.