💰Compound Interest Calculator
Calculate compound interest with adjustable compounding frequency, regular contributions, and a year-by-year growth breakdown — free and instant.
Growth Chart
Year-by-Year Breakdown
| Year | Balance | Total Invested | Interest Earned |
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Free Compound Interest Calculator Online
Want to see how your money grows over time? Our free Compound Interest Calculator shows you exactly how your savings or investments build the moment you enter your numbers. As a fast and reliable compound interest calculator, it instantly projects your future balance, total contributions, and total interest earned — so you can see the real power of compounding at a glance.
But it does more than a single number. Adjust the compounding frequency (daily, monthly, quarterly, or yearly), add regular monthly or yearly contributions, and view a clear year-by-year breakdown with a growth chart that shows how your balance accelerates over time. Whether you're planning for retirement, a house deposit, or a long-term savings goal, you'll see exactly where you're headed.
Simply enter your principal, rate, and timeframe to see your results instantly. No sign-up, no downloads, no limits — just clear projections whenever you need them.
About the Compound Interest Calculator
Key features
Adjustable compounding frequency
Choose daily, monthly, quarterly, or yearly compounding and immediately see the difference in your final balance. More frequent compounding means more interest on interest.
Regular contributions
Add a recurring monthly or yearly contribution to model a savings plan. The calculator adds each contribution at the right interval and applies compounding on top.
Year-by-year breakdown
A table showing balance, total contributions, and total interest earned at the end of each year — so you can see exactly when compound growth really starts to accelerate.
Growth chart
An SVG line chart plots your total balance against your contributions over the full investment period, making the exponential curve of compounding visually clear.
Who it's for
Retirement planners
Model a long-term investment or pension pot over 20–40 years and see how regular contributions dramatically compound the final balance.
Savers
Project a savings account, ISA, or fixed deposit to a specific target — a house deposit, emergency fund, or lump-sum goal.
Students & learners
Understand how compound interest works by changing variables and watching the numbers and chart update in real time.
Investors
Compare the impact of different annual return rates, compounding frequencies, and top-up amounts on a portfolio's future value.
How the calculation works
The calculator simulates growth month by month. For each month it applies the effective monthly interest rate derived from your chosen compounding frequency, then adds any regular contributions. This approach handles all combinations of contribution and compounding schedules accurately without rounding errors that arise from period mismatches.
Compounding frequencies are converted to an equivalent monthly rate: monthly compounding uses r/12 directly; quarterly uses (1 + r/4)1/3 − 1; daily uses (1 + r/365)365/12 − 1; yearly uses (1 + r)1/12 − 1. This ensures consistency regardless of the chosen frequency.
The results are gross projections and do not account for taxes, investment fees, or inflation. For a conservative real-terms estimate, subtract expected inflation and tax rates from the interest rate before calculating.
Frequently Asked Questions
How does the compound interest calculator work?
Enter your starting amount, interest rate, timeframe, and compounding frequency, and the tool instantly calculates your future balance, total contributions, and total interest earned — no button refresh needed.
Is this compound interest calculator free to use?
Yes, it's completely free with no sign-up, downloads, or limits. Run as many projections as you need, as often as you like.
What is compound interest?
Compound interest is interest earned on both your original principal and the interest already accumulated, so your balance grows faster over time compared to simple interest. The longer your money compounds, the more dramatically the growth accelerates.
Can I add regular contributions?
Yes. You can add recurring monthly or yearly contributions, and the calculator factors them into your projected growth and total interest. This helps you model a savings plan where you deposit regularly on top of your starting amount.
What compounding frequencies are supported?
You can choose how often interest compounds — daily (365 times per year), monthly (12 times), quarterly (4 times), or yearly (once). More frequent compounding generally produces a higher final balance for the same nominal rate.
Does it show a year-by-year breakdown?
Yes. The calculator displays a year-by-year breakdown table and a growth chart so you can see exactly how your balance, contributions, and interest accumulate over time. This makes it easy to spot when compound growth really starts to accelerate.
How accurate are the results?
The calculator uses the standard compound interest formula and accounts for your chosen frequency and contributions. Results are projections for planning and don't include taxes, fees, or inflation unless you factor them in manually.
Is my data stored anywhere?
No. Your figures are processed directly in your browser and are never stored or sent to a server, keeping your financial information completely private.
Does it work on mobile devices?
Yes, the calculator is fully responsive and works on smartphones, tablets, and desktops without any installation.
Does it account for inflation or taxes?
By default the calculator shows gross growth and doesn't deduct taxes or adjust for inflation. For real-terms planning, treat the result as a before-tax, before-inflation projection and subtract your expected tax rate and inflation rate from the interest rate to get a more conservative estimate.