A free monthly investment calculator — what if you invest every month?

Monthly Investment Calculator

“What could happen if I invest $X every month?” It is one of the most practical investing questions there is. This calculator answers it: enter a starting balance, a fixed monthly contribution, an assumed annual return and how long you stay invested — and see a projected future value, with your contributions separated from the estimated growth.

Calculate My Monthly Investment

100% free
Private by design
Monthly contributions
Contributions vs growth

01— The basics

What a monthly investment calculator answers

Investing a fixed amount on a regular schedule — sometimes called dollar-cost averaging — is one of the simplest ways to build wealth over time. This calculator focuses on the monthly version of that habit: it takes your starting balance, your monthly contribution, an assumed annual return and your time horizon, and projects where you could end up.

Starting balance

What you have invested today — zero works too if you are starting fresh.

Monthly contribution

The fixed amount you add every month, consistently over the whole period.

Assumed annual return

The yearly growth you assume. An estimate only — real returns vary.

Investment duration

How many years you stay invested and keep contributing monthly.

02— How it works

How monthly contributions compound

Each month your balance earns a share of the assumed annual return, and you add another contribution. Next month, that contribution — and its returns — join the balance and start earning too. Repeated over years, this compounding means the estimated growth can eventually outpace the total you contributed. The longer the horizon, the more pronounced the effect.

Estimates, not guarantees

Projections assume a steady annual return that real markets do not deliver. Returns fluctuate, investments can fall in value, and past performance does not predict future results. Treat the figure as a planning estimate, not a promise. Clear Budget provides calculations only and does not give personalized investment advice.

03— A simple example

A monthly investment example

Say you start with $1,000, invest $250 every month, and assume a 7% annual return over 25 years. Here is how the projected balance breaks down. (Illustrative only — actual returns vary.)

Starting balance

$1,000

Contributed over 25y

$76,000

$250/mo + start

Estimated growth

~$132,400

At 7% / year

Projected value

~$208,400

Of the projected ~$208,400, only about $76,000 is money you put in — the rest is estimated growth from compounding over 25 years. Bump the monthly contribution to $350 and the projected value rises accordingly. The same logic powers the broader Investment Growth Calculator and the Compound Growth Calculator.

04— The tool

Model monthly investing in Clear Budget

Add an investment line under Goals, Savings & Investing with a monthly contribution, then open “Add target or growth” to set a Current Amount (starting balance) and an Annual Yield. Clear Budget projects the balance across 1, 3, 5, 10, 20 and 30-year horizons, so you can see how a steady monthly habit could compound — all privately in your browser, no account needed.

Monthly habit

Model a fixed monthly contribution compounding over any number of years.

Contributions vs growth

See how much of the projection comes from your contributions versus estimated returns.

Private by design

Your numbers stay in your browser. No account, no sign-up, no tracking of your finances.

05— FAQ

Monthly investment calculator FAQ

What does a monthly investment calculator show?

It projects what a starting balance plus a fixed monthly contribution could grow to over a chosen duration, assuming a steady annual return. The result is split into total contributions and estimated growth so you can see where the balance comes from.

Are the projected returns guaranteed?

No. The projection uses an assumed annual return as a planning estimate. Real investment returns vary year to year and can be negative, so the actual result may be higher or lower. Clear Budget provides calculations only and does not give investment advice.

What if I invest on a different schedule?

This page focuses on monthly contributions. If you invest weekly, biweekly or annually, Clear Budget converts any frequency automatically — see the broader Investment Growth Calculator for any contribution schedule.

Does the starting balance matter?

Yes. A larger starting balance has longer to compound, so it contributes more estimated growth over time. You can also start from zero and rely entirely on monthly contributions — the calculator handles both.

Ready to see what monthly investing could do?

Open the free Clear Budget calculator, add a monthly investment line, set your starting balance and annual yield, and see projected balances across multiple horizons — privately, in your own browser. Estimates only; returns are not guaranteed.