Free mortgage, loan, BMI and everyday calculators that show the formula, worked examples and sources. No sign-up.
About FlareLodge
FlareLodge is a set of 20 free calculators for mortgages, loans, savings, retirement, health and everyday math. Each page shows the formula, explains the result in plain words, works through two examples and links its sources (CFPB, Federal Reserve, Freddie Mac, CDC). Calculations run in the browser. Free CSV data tables (mortgage payment by state and by loan amount, house affordability by salary, ideal weight and BMI by height) can be reused under CC BY 4.0, and the formula code is open source.
PlatformsWeb
LaunchedNov 4, 2026
Key features
- 20 calculators with the formula shown
- Two worked examples and cited sources on every page
- Free CSV data tables (CC BY 4.0)
- Embeddable calculator widgets
- No sign-up; runs in the browser
Made by
FlareLodge
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