About CalculatorFox
Calculations you can inspect, not a number you have to trust blindly.
CalculatorFox builds practical tools for money, health, maths, construction, business, and everyday decisions. The public calculators are free, work without an account, and do not save the figures you enter.
What makes the library different
Each calculator declares its inputs, outputs, method, checked examples, and sources in code. Pages render a real result and the calculation steps on the server before JavaScript adds live updates. Similar names that use the same calculation point to one preferred page instead of competing as duplicate search pages.
How the site is funded
Calculator use stays free and is supported by advertising on the free plan. A free account keeps 5 saved calculations and 1 private link, and can compare 2 sets of scenarios side by side. The Personal plan ($29 a year or $5 a month) removes ads and is for people who want to keep, compare, export and privately share many scenarios; Advisor adds client-facing branding, clients and several websites for people who present numbers to clients. A paid plan never changes a calculator answer.
Corrections and support
Methods, reference data, and rules can change. If a result or source looks wrong, contact support with the calculator name and a non-sensitive description. Never send private financial or medical figures.