Free Online Financial Calculators
Quickly estimate payments, project investment growth, and compare loan terms. No signup required.
Mortgage Calculator
Estimate monthly payments by loan amount, rate, and term.
Compound Interest Calculator
Project future balance with recurring contributions.
Auto Loan Calculator
Calculate car payments with price, rate, and down payment.
Why use simplefintools?
- Fast, accurate calculations
- Works on mobile and desktop
- Clear explanations of results
How to use these calculators
- Open a tool: Mortgage, Compound Interest, or Auto Loan.
- Enter your inputs (amount, rate, and term).
- Click Calculate to see your monthly payment or future balance.
- Adjust inputs to compare scenarios and find the best fit.
Mortgage payment estimator
Use our mortgage calculator to estimate your monthly home loan payment based on loan amount, interest rate, and term. Compare 15-year vs 30-year mortgages and see how rate changes affect affordability.
Compound interest growth
The compound interest calculator models growth with recurring contributions. Experiment with contribution size and time horizon to understand the impact of compounding on long-term savings.
Car payment calculator
Our auto loan calculator helps you plan a realistic car budget. Adjust vehicle price, down payment, APR, and term to see how each factor changes the monthly payment and total interest.
Frequently asked questions
Are these calculators accurate?
They use standard financial formulas. Actual results may vary due to fees, taxes, and lender policies. Treat outputs as estimates.
Do you store my inputs?
No. All calculations run in your browser. We do not store, transmit, or save your data.
How do I calculate compound interest monthly vs annually?
Our tool compounds monthly by default. For annual compounding, set contributions to yearly and adjust the rate accordingly.
Which APR should I use for car loans?
Use the APR quoted by your lender or a marketplace. If unsure, try a range (e.g., 4%–9%) to compare payments.