All tools · 💰 Finance Calculators
📈 Compound Interest Calculator
See how your money grows with compound interest. Set the initial deposit, monthly contribution, annual interest rate, compounding frequency, and time horizon — see the future value plus how much is principal vs interest earned.
Examples
PV $10,000, 7% annual, 30yFuture value: $76,123PV $0, $500/mo, 8% annual, 25yFuture value: $478,316 · Contributions $150k · Interest $328k$10k, 5%, 20 yearsAnnual: $26,533 · Daily: $27,180Continuous-ish compounding adds ~2.4% over annual.
Frequently asked questions
What is the compound interest formula?
A = P(1 + r/n)^(nt) where P is principal, r is annual rate, n is compounding periods per year, t is years. Add ongoing contributions and the formula grows but the principle is the same.
How important is compounding frequency?
Less than people think. At 5% over 20 years, monthly vs annual compounding differs by only ~1.2%. The big drivers are rate and time, not frequency.
Should I expect 7-8% returns from stocks?
The US stock market has returned roughly 10% nominal / 7% real (after inflation) historically. Future returns could be lower. Always plan with conservative assumptions.
What is the rule of 72?
A quick estimate: years to double = 72 / interest rate. At 7%, money doubles in ~10.3 years.
Does this account for taxes or inflation?
No. The result is nominal pre-tax. For real spending power, subtract 2-3% per year for inflation, and account for capital gains tax when you withdraw.
About this calculator
Compound Interest Calculator runs entirely in your browser using standard formulas. No data is sent to any server. We don't share your inputs with lenders, brokers, or anyone else — there's no funnel and no follow-up email.
Related tools
- 🏖️ Retirement Calculator — 401k / IRA / general retirement projection with employer match.
- 🎯 Savings Goal Calculator — How long to reach a target? Or how much to save monthly?
- 📈 Inflation Calculator — What is $X worth in Y years given Z% inflation? Past and future value.
Why this calculator
vs typical free finance-calculator sites
| RichCalcs | Typical free site | |
|---|---|---|
| Price | Free | Free |
| Signup required | No | Often (for full results) |
| Ads inside the calculator | No | Yes (banner + sidebar) |
| Lead capture (email / phone) | No | Yes — sold to lenders |
| Data sent to server | No (browser-only) | Yes (analytics + tracking) |
| Amortization schedule | Full table | Often summary only |
| Bookmarkable URL per calc | Yes | Mixed |
| Loads in under 1s | Yes (static) | Often slow (ad tracking) |
| Open source | Yes | No |