INVESTING
Investment Calculator
Free investment calculator. Estimate an ending balance, or solve for the contribution, return rate, starting amount, or time needed to reach a goal, with a year-by-year schedule.
THE GROWTH
What the money becomes.
In 25 years, $462,290.03 is built from $160,000.00 put in and $302,290.03 of interest. Interest supplies 65% of the total.
- Starting amount 2%
- Contributions 32%
- Interest 65%
| Line | Amount |
|---|---|
| Starting amount | $10,000.00 |
| Contributions | $150,000.00 |
| Interest | $302,290.03 |
| End balance | $462,290.03 |
THE PLAN
The assumptions behind it.
How the investment projection works
- Convert the annual return, at the compounding frequency you choose, into an equivalent monthly growth rate.
- Each month, add interest to the balance. Deposits go in before interest at the beginning of a period and after it at the end.
- Repeat for every month of the investment length, adding deposits monthly or once a year.
- When you solve for a contribution or starting amount, the calculator scales that one input to land exactly on your target. Return rate is found by repeated search, and length is the first month the balance reaches the target.
Worked example
Starting with $10,000 and adding $500 at the end of each month for 25 years at a 7% annual return, compounded monthly, ends near $462,290. About $160,000 of that is money you put in and about $302,290 is interest.
Assumptions and boundaries
- The return is constant every year and is not reduced by taxes, fees, or inflation.
- Contributions are the same amount each period and are never skipped or withdrawn.
- Length is rounded to the nearest whole month, and annual deposits happen only on full 12-month cycles.
Important limitation: Real investments rise and fall, so actual balances will differ from a smooth projection. Treat the result as an illustration of compounding, and test lower returns before relying on it.
Sources and review
Methodology and links reviewed . This educational estimate is not financial, tax, legal, investment, or lending advice.
Frequently asked questions
- What can this investment calculator solve for?
- It can estimate the end balance, or work backward from a target to find the contribution, return rate, starting amount, or length of time you need. Choose which one to find, then enter the rest.
- Does the timing of contributions matter?
- Yes. A deposit made at the beginning of a period earns interest for that period, while one made at the end does not, so beginning-of-period deposits finish slightly higher.
- How does compounding frequency change the result?
- More frequent compounding pays interest on interest sooner, which lifts the ending balance a little. The effect is small at ordinary rates, and continuous compounding is the upper limit.
- What return rate should I use?
- There is no guaranteed rate. A savings account or CD pays a stated rate, while stocks vary from year to year. Try a conservative, a middle, and an optimistic rate to see the range.