Free Online Calculators
CalcKit offers 280 free online calculators for math, health, finance, and unit conversion. Every calculator runs entirely in your browser with no sign-up, no account, and no data sent to any server. The collection spans four categories: Math (57) covering percentages, fractions, statistics, and geometry; Health (37) covering BMI, calories, body fat, and fitness; Finance (64) covering loans, mortgages, investing, and tax; and Conversion (122) covering length, weight, temperature, data size, and dozens of specialized units. Popular starting points include the Percentage Calculator, BMI Calculator, Mortgage Calculator, Tip Calculator, Currency Converter, Age Calculator. Each calculator page explains the formula it uses, walks through common use cases, and answers frequent questions, so you can both get a number and understand what it means. Read practical money and health math on the blog.