About this tool

A collection of 160 free browser-based calculators: paycheck, mortgage with PMI, credit card payoff, 401(k), compound interest, BMI, unit converters and everyday utilities. The US calculators use 2026 figures from the IRS and the Social Security Administration. Results update as you type, links can be shared with your numbers filled in, and every tool explains its formula and cites the official source behind its figures. No sign-up required.