401(k)
Calculator
Project your balance.
Open the 401(k) calculator →
Retirement
Investment Calculator
Project the future value of a starting amount plus monthly contributions at your expected return.
Future value
—
What it grows to.
| Total contributions | — |
|---|---|
| Investment growth | — |
| Starting amount | — |
| Ending balance | — |
Show our math
Enter your figures above to see the step-by-step working.
Everything computed client-sideEverything computed client-side — nothing leaves this page
How the Investment Calculator Works
This calculator projects what an investment grows to when you start with a lump sum and add to it every month. It compounds monthly: each month the balance earns one-twelfth of your annual return, then your contribution is added. Over years and decades the growth compounds on itself, which is why the “investment growth” line eventually dwarfs what you actually paid in.
Enter zero in either box to model just a lump sum or just monthly deposits. The return you choose matters a great deal — a broad stock-and-bond portfolio has historically returned roughly 6–8% a year before inflation, but real returns bounce around, so read the result as a projection rather than a guarantee.
FV = start × (1 + i)n + monthly × [(1 + i)n − 1] ÷ i
Frequently Asked Questions
How much will my investment grow?
Enter a starting amount, monthly contribution, expected return and number of years. The calculator compounds monthly and shows the ending balance along with how much was contributions versus growth.
What return rate is realistic?
Historically a diversified stock-and-bond portfolio has returned about 6–8% per year before inflation. Being conservative — say 5–6% — gives a more cautious estimate, since future returns are never guaranteed.
Does it account for inflation or taxes?
No — it shows nominal growth. To gauge purchasing power, subtract expected inflation (around 2–3%) from your return, and remember tax-advantaged accounts like IRAs and 401(k)s change the after-tax picture.
More From The Desk
Same plain method, different figures401(k)
Annuity
Calculator
Present and future value.
Open the annuity calculator →Roth vs Traditional
401(k)
After-tax comparison.
Open the Roth 401(k) calculator →RMD
Calculator
Required minimum distribution.
Open the RMD calculator →