Investment calculator
See what investing every month could grow to, with a yearly increase and an optional lump sum.
Results
Value after 15 years
$274,996.54
This is what investing every month could grow to in 15 years at 10% a year, raising the monthly amount by 5% each year.
- Total invested
- $129,471.38
- Estimated growth
- $145,525.16
- Monthly amount in the final year
- $989.97
Amount invested and its value
Saving and PDF download use a free account. Everything else works without one.
How it works
You invest a fixed amount at the start of every month, so each deposit earns at least a month of growth. Returns are applied monthly at the yearly rate ÷ 12. With a yearly increase, the monthly amount rises by that percentage at the start of each new year. A lump sum is invested at the very beginning and grows alongside your monthly deposits.
Formula
- i = expected yearly return ÷ 12 ÷ 100, n = years × 12
- Each month: value = (value + monthly amount) × (1 + i)
- Monthly amount in year y = first amount × (1 + yearly increase ÷ 100)^(y − 1)
- No yearly increase: value = monthly amount × ((1 + i)^n − 1) ÷ i × (1 + i)
Frequently asked questions
What return should I expect?
Nobody can know future returns. Use a cautious long-run average for the kind of investment you hold, and try a lower figure too so you can see a range. Real returns go up and down from year to year rather than arriving smoothly.
Why raise the amount each year?
Most people earn more over time, so raising your investment each year is a natural way to keep pace. Even a small yearly increase makes a large difference over long periods because the bigger later deposits still have years to grow.
Is the result guaranteed?
No. This is an estimate based on a steady return you choose. Fees, taxes and market swings will change the real outcome, and the order of good and bad years matters too.
How is this different from the compound interest calculator?
This one is built for regular investing: deposits at the start of each month, a yearly increase and an optional lump sum. The compound interest calculator focuses on a starting amount, a choice of how often interest is added, and money added at the end of each month.
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- Retirement calculatorSee how much you need saved by retirement and the extra monthly saving to get there.
- ROI calculatorSee how much an investment made or lost, as a total percentage and as a yearly rate.
Results are estimates only, not financial advice. Read the disclaimer.