Compound Interest Calculator
Growth over time.
Growth over time.
This is a simplified estimate for general information only — not financial, tax, or legal advice. Real figures vary by lender, rate, jurisdiction and your own circumstances, so confirm with a qualified professional before acting.
How to use Compound Interest Calculator
- Enter your principal, annual rate, and number of years
- Choose how often interest compounds, annually through daily
- Add an optional monthly contribution
- Read your final balance, total contributions, and interest earned
About Compound Interest Calculator
This compound interest calculator shows how a starting amount grows once the interest it earns starts earning interest of its own. Enter a principal, an annual interest rate, and a number of years, then pick how often the interest compounds, from annually all the way down to daily. It instantly returns your final balance, the total you put in, and the total interest earned, so you can figure, compute, or double-check compound growth without touching a spreadsheet or the P(1 + r/n)^(nt) formula yourself.
Because you can set compounding to daily, it answers the common "compound interest per day" question directly: switch the frequency to daily and the balance reflects interest added every single day. Add an optional monthly contribution and the calculator layers regular deposits on top of the principal, which is useful for modeling a savings habit or a recurring investment. Every field is live, so you can compare rates, timelines, and compounding intervals side by side, or sanity-check the number a tool like NerdWallet gave you.
It is completely free with no sign-up, and it runs entirely in your browser. Nothing you type is sent to a server or stored anywhere, so your principal, rate, and contribution figures stay private on your own device.
Frequently asked questions
- Is the compound interest calculator free to use?
- Yes. It is completely free with no account, sign-up, or subscription required. You can run as many calculations as you like.
- How do I calculate compound interest?
- Enter your starting principal, the annual interest rate, the number of years, and how often interest compounds, then the calculator does the math for you. It applies the standard formula P(1 + r/n)^(nt) and displays your final balance, total contributions, and total interest earned instantly.
- How is compound interest calculated?
- The principal grows by P(1 + r/n)^(nt), where P is the principal, r is the annual rate as a decimal, n is the number of compounding periods per year, and t is the number of years. Monthly contributions are handled as a separate future-value calculation and added to the principal's growth.
- How do I calculate compound interest per day?
- Set the compounding frequency to daily. The calculator then compounds the interest once every day of the year, so the balance grows a little faster than the same rate compounded monthly or annually. This answers the common per-day compound interest question without any manual math.
- What does compounding frequency mean?
- Compounding frequency is how often interest is added to your balance so it starts earning interest itself. You can choose annually, semi-annually, quarterly, monthly, or daily. More frequent compounding produces a slightly higher final balance for the same rate.
- Can I include regular monthly contributions?
- Yes. The monthly contribution field is optional. When you enter an amount, the calculator treats each deposit as made at the end of the month and adds the future value of all those contributions to your final balance.
- How much will my money grow with compound interest?
- Enter your numbers and the tool shows the final balance alongside how much of it is your own deposits versus interest earned. Adjust the rate, the number of years, or the compounding frequency and the results update immediately, so you can see exactly how each change affects the growth.
- How is this different from the NerdWallet compound interest calculator?
- It performs the same core calculation, future value from a principal, rate, term, compounding frequency, and optional contributions. The difference is that this version runs entirely in your browser with no sign-up and doesn't store or transmit anything you enter, making it handy for quickly checking a figure from another calculator.
- Does the calculator account for taxes and inflation?
- No. The result is a pre-tax estimate that does not deduct taxes, account fees, or inflation. It is intended for quick planning and comparison, not as financial advice.
- Is my data uploaded or stored anywhere?
- No. All calculations happen locally in your browser. Nothing you enter is transmitted to a server, saved, or shared, so your financial figures stay private on your device.