Investment Calculator
Enter what you invest at the start, what you add each month, an expected annual return and the number of years. The calculator shows the future value, splits it into what you paid in and what growth added, and lists the balance for every year.
Last updated November 4, 2026
Result
Value after 20 years = $300,850.72
| Result | Value |
|---|---|
| Future value | $300,850.72 |
| Total contributions | $130,000.00 |
| Investment growth | $170,850.72 |
| Growth share of the balance | 56.789% |
| Effective annual yield | 7.229% |
| Year | Contributed | Growth | Balance |
|---|---|---|---|
| 1 | $16,000.00 | $919.19 | $16,919.19 |
| 2 | $22,000.00 | $2,338.58 | $24,338.58 |
| 3 | $28,000.00 | $4,294.31 | $32,294.31 |
| 4 | $34,000.00 | $6,825.16 | $40,825.16 |
| 5 | $40,000.00 | $9,972.70 | $49,972.70 |
| 6 | $46,000.00 | $13,781.53 | $59,781.53 |
| 7 | $52,000.00 | $18,299.43 | $70,299.43 |
| 8 | $58,000.00 | $23,577.68 | $81,577.68 |
| 9 | $64,000.00 | $29,671.22 | $93,671.22 |
| 10 | $70,000.00 | $36,639.02 | $106,639.02 |
| 11 | $76,000.00 | $44,544.25 | $120,544.25 |
| 12 | $82,000.00 | $53,454.70 | $135,454.70 |
| 13 | $88,000.00 | $63,443.02 | $151,443.02 |
| 14 | $94,000.00 | $74,587.14 | $168,587.14 |
| 15 | $100,000.00 | $86,970.62 | $186,970.62 |
| 16 | $106,000.00 | $100,683.03 | $206,683.03 |
| 17 | $112,000.00 | $115,820.45 | $227,820.45 |
| 18 | $118,000.00 | $132,485.91 | $250,485.91 |
| 19 | $124,000.00 | $150,789.85 | $274,789.85 |
| 20 | $130,000.00 | $170,850.72 | $300,850.72 |
A projection at one constant return. Real returns vary year to year and can be negative; taxes, fees and inflation are not included.
Show the work
Formula: Value = initial × G^months + each contribution grown by G for the months it stays invested, where G = (1 + rate ÷ 12)^(12 ÷ 12) is the monthly growth factor.
- Monthly growth factor: G = (1 + 7% ÷ 12)^(12 ÷ 12) = 1.00583333. That is 240 months of growth.
- Initial investment: $10,000.00 × G^240 = $40,387.39.
- 240 contributions of $500.00 (end of each month) grow to $300,850.72 − $40,387.39 = $260,463.33.
- Total contributions: $10,000.00 + 240 × $500.00 = $130,000.00.
- Growth: $300,850.72 − $130,000.00 = $170,850.72, which is 56.789% of the final balance.
Result: Value after 20 years = $300,850.72
How the projection works
Value = initial × G^m + monthly × (G^m − 1) ÷ (G − 1)
G = (1 + r ÷ n)^(n ÷ 12)
G is the growth factor for one month, built from the annual return r and the number of compounding periods per year n. The initial amount grows for all m months. Each monthly contribution grows for the months it stays invested, which gives the second term for contributions made at the end of each month.
Contributions are the initial amount plus every monthly deposit. Growth is the final value minus contributions. At a 0 percent return the value equals contributions and growth is zero.
See how we calculate for the formulas, sources and review schedule behind every calculator.
Contributions versus growth
Early on, most of the balance is money you paid in. Over longer periods, growth earns on earlier growth, so its share rises. The year-by-year table shows this shift, and the growth share row gives the final split.
What this does not model
The return is one constant rate, while real returns change every year and can be negative. The tool accepts returns from 0 to 100 percent. Taxes, fees, inflation and changes to your contributions are not included, so treat the result as an illustration.
General information, not financial advice
This calculator gives a general estimate from the numbers you enter. It is not financial or tax advice, and your actual results can differ. Check important decisions with a qualified professional or the official source.
Sources
Official and primary sources for the statements on this page. Their authors have not reviewed or endorsed this page.
- U.S. Securities and Exchange Commission, Investor.gov, Compound Interest (glossary).. Defines compound interest as interest paid on principal and on accumulated interest.
Standard compound growth with regular contributions, shared with engines/interest.ts. A projection at a constant rate, not a forecast or financial advice.
How to use the Investment Calculator
- Enter the initial investment and the monthly contribution.
- Enter the expected annual return and the number of years.
- Choose the compounding frequency and when each contribution is made.
- Read the future value, the growth and the yearly table.
- Use Copy, Print or Share to keep the result.
Worked example
Investing 10,000 and adding 500 a month at 7 percent compounded monthly for 20 years grows to 300,850.72. You paid in 130,000, so growth is 170,850.72, or 56.8 percent of the balance.
| Inputs | Final value | Contributed | Growth |
|---|---|---|---|
| 10,000 + 500/mo, 7%, 20 yr | 300,850.72 | 130,000 | 170,850.72 |
| 0 + 200/mo, 6%, 30 yr | 200,903.01 | 72,000 | 128,903.01 |
| 5,000 + 250/mo, 8%, 10 yr | 56,834.71 | 35,000 | 21,834.71 |
Frequently asked questions
What annual return should I enter?
Nobody can know future returns. Try a few rates, such as a cautious one and an optimistic one, and compare how much the result moves.
Does it matter if I contribute at the start or end of the month?
Slightly. Start-of-month contributions earn one extra month of growth, so the final value is a little higher than with end-of-month deposits.
How is this different from the compound interest calculator?
It is built around monthly contributions and shows the growth share of the balance. The compound interest calculator also supports yearly deposits and partial years.
Are taxes and fees included in the result?
No. Subtract your expected fees from the return you enter, and remember that taxes on gains can lower what you keep.