Monthly Investment Calculator
No lump sum needed — just consistency. See what investing a fixed amount every month builds over the years, and how much more you get by raising the amount a little each year.
▸ Show year-by-year breakdown
| Period | Monthly | Invested | Growth | Balance |
|---|
Estimates are for illustration and education only — not financial advice. Returns are assumed constant and are not guaranteed.
Why monthly investing works so well
Investing monthly — often called dollar-cost averaging when buying market funds — turns saving into a habit instead of a decision. Each deposit starts compounding the moment it lands, and because you buy at many different prices, you never put everything in at the worst moment. It's how most real wealth gets built: not with one big bet, but with hundreds of small automatic ones.
The growth share stat
Watch the third stat as you extend the horizon. Early on, nearly the whole balance is your own deposits. Around year 20–25 at typical stock returns, growth overtakes contributions — more than half your balance is money your money made. That crossover is the entire argument for starting early.
The annual raise is a superpower
A fixed $300/month quietly shrinks in real terms as your income and prices rise. Raising the amount just 5% a year — roughly matching salary growth — can add 30–50% to the final balance over long horizons, with barely any felt sacrifice. Try the toggles and compare.
Related tools
Have a starting sum too? The compound interest calculator combines a lump sum with contributions, plus inflation and tax. Working toward a specific number? The savings goal calculator solves for the monthly amount you need.
What a monthly investment builds at 7%
Final balance from investing a fixed amount every month at a 7% annual return, compounded monthly, with no annual raise.
| Per month | 10 years | 20 years | 30 years | 40 years |
|---|---|---|---|---|
| $100 | $17,308 | $52,093 | $121,997 | $262,481 |
| $250 | $43,271 | $130,232 | $304,993 | $656,203 |
| $500 | $86,542 | $260,463 | $609,985 | $1,312,407 |
| $1,000 | $173,085 | $520,927 | $1,219,971 | $2,624,813 |
| $2,000 | $346,170 | $1,041,853 | $2,439,941 | $5,249,627 |
Figures are rounded and assume a constant 7% with monthly compounding, deposits at end of month — illustrative only.
How steady monthly investing grows
Each monthly deposit is its own small investment that compounds from the day it lands. Summed across the years, they form the future value of a growing annuity.