Everyday finance calculator
Compound Interest Calculator
Project investment growth from an initial balance, monthly contributions, return rate, and time.
Investing with a clear plan →Reviewed by Syvoq Editorial Team ·
The smooth curve is a model, not a promise from the market
Compounding shows how a starting balance, regular contributions, time, and an assumed return interact. It is excellent for comparing habits: starting now versus later, adding €50 more each month, or paying lower fees. It is not a forecast of the exact account balance on a future birthday.
Run at least three return assumptions and consider inflation when the goal is stated in today’s prices. For investments, actual returns arrive unevenly and may be negative for long periods. For savings products, rates can change. The most dependable input is often the contribution you control, so focus on a payment that can continue through ordinary setbacks.
A real-world check
A small contribution increase that has years to work
Moving from €250 to €300 a month may feel modest today. Over a long horizon, every extra contribution has time to earn returns of its own. Compare that change under cautious and stronger assumptions; if it helps in both, it is a robust lever even though neither final value is guaranteed.
How to read the result
Contributions dominate early
That is normal. During the first years, the amount you add is usually doing more work than accumulated returns.
Returns dominate later
The projection becomes more sensitive to the assumed rate, which is exactly why a range matters.
The target still looks distant
Test the three controllable levers separately: contribution, deadline, and goal size.
What this calculator cannot know
- The result does not include product fees, taxes, inflation, changing rates, missed contributions, or market volatility.
- A constant annual return hides sequence risk: two paths with the same average can feel and finish differently.
What to do next
- Save cautious, middle, and optimistic versions rather than one favorite result.
- Check whether the monthly contribution still leaves an emergency buffer and near-term goals intact.
- Review annually or after a material life change, not every time markets move.
Connect the portfolio
See investments inside your full net worth
Track holdings, accounts, goals, and liabilities together instead of judging the portfolio in isolation.
Common questions
About this calculator
What return should I use?
Use a conservative estimate for planning. Many people test several return assumptions to understand downside and upside cases.
Does this include taxes or fees?
No. Reduce the expected return if you want to approximate taxes, platform fees, or fund expenses.
How it works
The expected annual return is converted to a monthly rate.
Monthly contributions are treated as end-of-month contributions.
Actual investments can be volatile, so this is a planning projection rather than a guarantee.
Educational planning estimate. It does not replace an official calculation or individualized financial, tax, or legal advice.
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