Mortgage Calculator
Estimate monthly mortgage payments including taxes, insurance and HOA.
Compound Interest Calculator
See how savings grow when interest earns interest — plus optional monthly contributions.
Disclaimer: This calculator gives estimates only and is not financial, tax, or legal advice. Figures can differ from lender, employer, or official calculations. Please confirm important decisions with a qualified professional. See our full disclaimer.
The compound interest formula
A = P(1 + r/n)nt, where A is the final amount, P the principal, r the annual rate, n the number of compounding periods per year and t the years. This calculator simulates growth month by month so regular monthly contributions are included as well.
Worked example
$10,000 at 7% compounded monthly for 20 years, with no contributions, grows to about $40,387. Without compounding — simple interest only — it would be just $24,000.
How to use this calculator
- Enter your starting amount and any monthly contribution.
- Add the expected annual rate and number of years.
- Choose how often interest compounds, then select Calculate.
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Frequently asked questions
What is compound interest?
Interest calculated on both the original amount and on interest already earned, so growth accelerates over time.
Are investment returns guaranteed?
No. Investment returns vary and can fall. This calculator assumes a steady rate purely for illustration.