About Watcharu Finance

Watcharu Finance is a set of free financial calculators — mortgage, auto and personal loan, debt payoff, compound interest, retirement, and more. Every calculation runs entirely in your browser. Nothing you enter is uploaded, logged, or stored on a server.

How the numbers are calculated

Each calculator uses standard finance formulas — the amortization equation for loan payments, time-value-of-money formulas for savings and investing, and published effective rates for state-specific figures. The math is implemented in a single tested library and checked against externally published reference figures. Results are estimates for planning; they are not quotes, offers, or financial, tax, or legal advice.

Where the data comes from

State-level figures — sales-tax rates, effective property-tax rates, median home prices, median household income, and average insurance premiums — come from public sources including the Tax Foundation, ATTOM, the U.S. Census Bureau, the NAIC, and Redfin. They are approximate and are refreshed periodically; the current data was last reviewed in September 2026. Always confirm rates and figures with your lender, county assessor, or a licensed professional before making a decision.

Contact

Corrections and suggestions are welcome. Reach us at hello@watcharu.com.