Financial simulation tool
Complete Compound Interest Calculator with graph, table, and monthly projection
Simulate recurring contributions, compare monthly and equivalent annual rates, and track how your balance may grow over time without treating the projection as a return promise.
Includes
- Initial capital, deposit, rate, and term
- Conversion of annual to equivalent monthly rate
- Financial summary, graph, and month-by-month table
- Copy result and clear fields
- Simulation summary, related tools, and result explanations
- Examples comparing contributions, terms, and rates
- Notice about inflation, taxes, fees, and market risk
Projection updated as fields change
Set up the complete compound interest scenario and track wealth growth
Adjust initial capital, monthly contribution, rate, and term to visualize final balance, accumulated interest, equivalent rate, growth chart, and detailed table.
Enter an initial capital of zero or greater.
Enter a monthly contribution of zero or greater.
Enter an interest rate of zero or greater.
Enter a term greater than zero.
Rate type
Time unit
Summary
Enter valid initial capital, contributions, rate, and term to generate the complete compound interest projection.
Simulation highlight
Chart waiting for valid simulation.
The chart will appear here when the simulation is valid.
The monthly table will appear here when the simulation is valid.
Capital, rate, and contributions build up month-by-month
- 1. Set initial capital, contribution, rate, and time horizon.
- 2. The calculator converts annual rates to monthly equivalents when needed.
- 3. Each month, interest is calculated on the total accumulated balance.
- 4. The monthly contribution is added at the end of the period, updating the projection.
Ideal for planning goals, deposits, and compound interest effect
- Use the simulation to compare scenarios with different rates, terms, and contributions.
- The longer the time, the stronger the compounding growth effect becomes.
- The chart helps visualize the growth pace, while the table details each month.
- Verifiable example: with 1,000 initial capital, a 100 monthly contribution, a 12% annual rate, and a one-year term, the simulation creates 12 rows, shows 2,200 invested, and projects approximately 2,384.65 before external costs.
- Note that the tool does not consider taxes, inflation, operating fees, changes in returns, or market risk.
- The result is a mathematical projection for planning, not investment advice or a guarantee of return.
FAQ
Summary
What does this compound interest calculator do?
The tool projects final balance, invested amount, accumulated interest, equivalent monthly rate, growth chart, and monthly table from initial capital, contribution, rate, and term.
Is the monthly contribution added at the start or end of the month?
In this simulation, the monthly contribution is added at the end of each month; this assumption affects the result and should be compared with the conditions of the scenario being analyzed.
What happens when the interest rate is annual?
The calculator converts the annual rate to the equivalent monthly rate before generating the simulation, ensuring consistency.
Which costs and risks are outside the projection?
The simulation does not automatically subtract inflation, taxes, operating fees, changes in returns, or market risk. Use it to compare scenarios and confirm the financial product conditions before making a decision.
Is the projection financial advice?
No. It shows the mathematical effect of the values entered and does not evaluate your profile, goals, liquidity, or tolerance for losses. Financial decisions require analysis suited to your context.
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The simulator is for people planning savings, comparing terms and rates, or wanting to understand compound interest before talking to a financial institution.
- Compare starting with more capital versus contributing every month.
- Test monthly or yearly rates without converting by hand.
- Follow month by month how much came from contributions and how much from interest.
How to simulate
- 1. Enter the initial capital and the monthly contribution.
- 2. Enter the rate and choose whether it is monthly or yearly.
- 3. Enter the term in months or years.
- 4. Read the summary, the chart, and the monthly table.
Each month's interest becomes part of the next month's base
Every month, interest is calculated on the current balance; then that month's contribution is added.
Yearly rate
It is converted to the equivalent monthly rate.
12% a year is about 0.95% a month, not 1%.
Contribution
It is added at the end of each month.
That is why the first contribution only earns interest from the following month.
Result
It separates the total invested from accumulated interest.
So you can see how much of the final amount came from your own money.
1,000 upfront and 100 a month, at 1% a month for 12 months
Fill in the fields with the values below, a monthly rate, and a term in months.
Total invested
2,200.00
Accumulated interest
195.08
Final amount
2,395.08
Change only the term to 24 months and compare how much the interest grows.
A mathematical projection, not a promise
The simulator applies a fixed rate for the whole period.
- Inflation, taxes, and management fees are not deducted.
- Real returns vary over time and can be negative.
- The result is not investment advice.
Check the product's conditions
Before investing, compare the net rate, taxation, and liquidity stated by the financial institution.