Personal finance calculators that show their work
Enter your tax situation once and every calculator uses it. Everything runs in your browser, and share links carry your numbers without storing them anywhere.
Mortgage
Mortgage payoff planner
Plan extra payments month by month, compare refinance offers with break-even dates, and see whether prepaying beats Treasuries after tax.
Open planner → Bonds & cashTax-equivalent yield
Rank CDs, Treasuries, munis and money market funds by what you keep after federal, state and investment income tax.
Compare yields → Credit cards0% APR savings arbitrage
Find out what a 0% intro APR card is worth when the cash sits in high-yield savings or T-bills, after minimums and taxes.
Run the numbers →