A free compound growth calculator — watch the snowball, in plain language

Compound Growth Calculator

Compound growth is one of the most useful ideas in personal finance — and it is simpler than it sounds. This calculator shows how an initial amount plus recurring contributions can potentially grow when you apply an assumed annual percentage, year after year. The explanation stays beginner-friendly, and the result is always shown as an estimate, never a promise.

Calculate Compound Growth

100% free
Private by design
Beginner-friendly
Contributions vs growth

01— The basics

What is compound growth?

Compound growth means earning returns on your returns. Start with an amount, apply a percentage for the year, and you have growth. Next year, that percentage applies to the original amount and the first year’s growth — so the base keeps growing. Add regular contributions and each one starts compounding too. Over many years, the estimated growth can grow larger than the money you put in. That is the snowball effect.

Initial amount

The starting balance you begin with — the seed the snowball rolls from.

Recurring contributions

Amounts you add regularly. Each one compounds from the moment it joins.

Annual percentage

The assumed yearly growth rate. An estimate only — real rates vary.

Duration

How long the balance compounds. More time means a bigger snowball.

02— How it works

How the snowball builds, step by step

Picture $1,000 growing at 5% a year. After year one it is $1,050 — you earned $50. In year two the 5% applies to $1,050, earning $52.50, so the balance is $1,102.50. Each year the amount earned grows because the base is larger. Add a monthly contribution and the snowball gathers more snow every month. The calculator does this math for any starting amount, contribution, percentage and duration you enter.

An assumption, not a promise

The annual percentage is an assumption for planning. Real growth fluctuates — savings rates change, investments rise and fall, and you can lose money. The projection shows what steady compounding could look like, not what will happen. Clear Budget provides calculations only and does not give investment advice or promise future returns.

03— A simple example

A compound growth example

Start with $500, add $100 a month, and assume 5% annual growth over 15 years. Here is how the snowball breaks down. (Illustrative only — actual growth varies.)

Initial amount

$500

Contributed over 15y

$18,500

$100/mo + start

Estimated growth

~$12,300

At 5% / year

Projected value

~$30,800

You put in about $18,500 over 15 years, and compounding adds an estimated $12,300 on top — growth that came from time and the snowball, not from your contributions. Try a longer duration and watch the growth share grow. For monthly-focused investing, see the Monthly Investment Calculator.

04— The tool

See compounding in Clear Budget

Add any savings or investment line under Goals, Savings & Investing, then open “Add target or growth” and enter a Current Amount and an Annual Yield. Clear Budget projects the balance across 1, 3, 5, 10, 20 and 30-year horizons so you can watch the snowball build over different timeframes — privately in your browser, no account needed.

Beginner-friendly

Plain-language compounding with contributions clearly separated from estimated growth.

Multiple horizons

Project across 1 to 30 years to see how time changes the snowball.

Private by design

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

05— FAQ

Compound growth calculator FAQ

What is compound growth, in plain terms?

Compound growth is when the growth your money earns starts earning growth too. In the first year you earn a return on your original amount. In the second year you earn a return on the original amount plus the first year’s growth — so the base that earns keeps getting larger. Over time, that snowball effect is what makes the estimated growth outpace what you put in.

How is the projected value calculated?

Clear Budget applies your assumed annual percentage to the starting amount, adds each recurring contribution, and compounds the growing balance over the duration you choose. The result separates total contributions from estimated growth so you can see the snowball clearly.

Is the projected growth a guarantee?

No. The percentage you enter is an assumption. Real returns vary year to year and can be negative, especially with investments. The projection is a beginner-friendly planning estimate, not a promise. Clear Budget provides calculations only and does not give investment advice.

Does this work for savings as well as investments?

Yes. The same math applies to any balance that earns a percentage — a savings account, a goal fund or an investment. Enter the annual percentage that fits the asset. For investment-focused projections, see the Investment Growth Calculator.

Ready to watch compounding work?

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