MaCalculatrice is an online calculation platform that provides access to more than 3000 free calculation tools. The service covers nine thematic areas: mathematics, finance, sport and running, health and wellness, pregnancy and maternity, work and time, measurements and geometry, statistics, and astrology. All calculators are accessible without registration and deliver immediate results. Each tool page explains the formula used and cites sources when they are known, following an editorial protocol that includes updates when official scales change. The finance section includes over 80 tax calculators covering income tax, local taxes, business taxation, and special regimes, using the 2026 tax brackets published by Service Public. Salary calculators handle gross-to-net conversions for various employment statuses, bonuses, severance indemnities, and social security contributions based on official URSSAF rates. Users can also calculate VAT, profit margins, legal interest rates, and employee leave or end-of-contract premiums. The platform addresses a range of use cases. Students and educators can calculate averages, solve geometry problems, and study statistics and probabilities. Runners can determine race pace, aerobic speed, and training splits. Expectant parents can calculate due dates, track pregnancy weeks, and estimate weight gain. Additional calculators cover surfaces, volumes, unit conversions, electrical power, and cable sections. The site also includes astrology tools such as ascendant and lunar sign calculators. Results provided by the calculators are presented as estimates and are intended to be verified before important decisions. Pages are signed by the editorial team and are not reviewed by professionals in the respective fields. The platform also partners with Indy, a service for auto-entrepreneurs that automates transaction categorization and pre-fills declarations.