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Transparent Math
Every formula is documented. Understand exactly how your results are calculated.
Popular calculators
Our most-used tools to help you make informed financial decisions.
Retirement Calculator
Estimate the savings needed and track progress toward funding your desired retirement lifestyle.
Compound Interest Calculator
See how your money grows over time with the power of compound interest.
Dividend Growth Calculator
Project future income from a dividend stock portfolio based on initial yield and growth rate.
DRIP Forecast Calculator
Model the future value of a dividend reinvestment plan, showing the power of compounding dividends.
Rental Property ROI Calculator
Calculate the annual return on investment for a rental property, factoring in income, expenses, and appreciation.
Buy vs Rent Calculator
Compare the true cost of homeownership versus renting over time to make an informed decision.
Frequently asked questions
Is PennyMath really free?
Yes, 100% free. No premium tiers, no hidden fees, no "upgrade to unlock" features. Every calculator is fully functional without any payment required.
How accurate are the calculations?
We use industry-standard financial formulas and document our methodology for each calculator. While our tools provide solid estimates, they're meant for planning purposes and shouldn't replace professional financial advice.
Is my financial data private?
Absolutely. All calculations run locally in your browser. We don't collect, store, or transmit any of your financial data. There are no accounts, no cookies tracking your inputs, and no analytics on what you calculate.
Can I see how the calculations work?
Yes! Check out our methodology page where we explain the formulas and assumptions behind each calculator. We believe in transparent math.
Do I need to create an account?
No. Just open a calculator and start using it. No sign-ups, no email verification, no friction. We built PennyMath to be as simple as possible.
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