Compound Interest Calculator - Investment Growth | Morph

See what your money becomes over time

This compound interest calculator shows how an investment or savings balance grows when your returns earn returns of their own. You enter a starting amount, an annual rate, how long you're investing, and any regular contributions you plan to add, and it projects the balance year by year - separating how much you put in from how much the growth added.

Compounding is the reason small, consistent investing beats large, occasional saving. Einstein supposedly called it the eighth wonder of the world; whether or not he actually said it, the effect is real. Money that stays invested doesn't grow in a straight line - it curves upward, because each year's gains become next year's principal.

What the calculator accounts for

Compounding frequency - whether interest is applied yearly, monthly, or daily changes the result. More frequent compounding grows slightly faster at the same nominal rate.
Regular contributions - adding a fixed amount each month is where the real magic happens for most people. The calculator shows the difference your contributions make versus a one-time deposit.
Time - the single biggest lever. Because growth compounds, an extra ten years often matters more than a higher starting balance. Starting early genuinely beats starting big.
Contribution vs. growth split - you can see exactly how much of the final number is your own money and how much the compounding earned for you, which is usually the most eye-opening part.

Why a browser-based tool

Your financial numbers stay on your device. There's no account, no email gate, and nothing sent to a server - the projection is calculated locally in your browser. Run as many scenarios as you like, compare an aggressive contribution plan against a conservative one, and nothing about your finances is stored or shared.

A few honest caveats. This is a projection, not a promise. Real investment returns are not a flat annual rate - markets go up and down, and a stretch of bad years early on hurts more than the average suggests. The calculator also shows pre-tax, pre-inflation figures unless you adjust the rate yourself; a 7 percent return feels smaller after inflation takes its cut. Use a realistic long-term rate rather than a best-case one, and treat the output as a planning aid, not a guarantee.

For home-buying math, the mortgage calculator handles loan payoff and interest. The currency converter is handy if you're modeling investments in another currency.

How to use

Enter your starting amount — Type the initial balance you're beginning with. It can be zero if you're starting from scratch and relying on regular contributions.
Set the interest or return rate — Enter a realistic annual percentage. For long-term stock-market planning, many people use a conservative figure adjusted for inflation rather than a best-case historical average.
Add your contributions — Set how much you'll add on a regular schedule, such as monthly. This is where consistent investing pays off the most over time.
Choose the time frame and compounding — Pick how many years you'll invest and how often interest compounds (yearly, monthly, or daily).
Review the growth breakdown — See the final balance and how it splits between the money you contributed and the growth compounding earned. Adjust any input to compare scenarios instantly.

Frequently asked questions

What's the difference between simple and compound interest?

Simple interest is calculated only on your original principal, so it grows in a straight line. Compound interest is calculated on your principal plus all the interest already earned, so growth accelerates over time. This calculator models compound interest, which is how most savings accounts, investments, and loans actually work.

Does compounding frequency really change the result?

Yes, though less than people expect at the same rate. Interest that compounds monthly grows slightly faster than interest compounding annually because gains start earning sooner. The longer your time frame, the more that small difference adds up.

Are the projected returns guaranteed?

No. The calculator assumes a steady annual rate, but real investments fluctuate year to year and can lose value. Use it as a planning estimate with a realistic rate, and remember that markets don't deliver smooth, identical returns every year.

Is my financial information saved or uploaded?

No. Everything is calculated in your browser on your own device. There's no account, no server call, and your amounts and rates are never stored or shared. You can run unlimited scenarios privately.

Should I account for inflation and taxes?

For a realistic picture, yes. The default projection is pre-tax and pre-inflation. A 7 percent return is worth less in real spending power once inflation is subtracted, and investment gains may be taxed. To see inflation-adjusted growth, enter a lower real rate of return.