Math & Calculator Tools
Rule of Three, percentages, fractions and area calculation — our 10 math calculators solve your problems step by step, with full solution paths and clear visualizations.
Area Calculator
Calculate area and perimeter: rectangle, circle, triangle, trapezoid – or draw irregular shapes yourself
Calculate now →Percentage Calculator
Calculate percentages: base value, percentage, change, markup & discount
Calculate now →Fraction Calculator
Add, subtract, multiply, divide, simplify and convert fractions
Calculate now →Rule of Three Calculator
Proportional, inverse and compound rule of three with step-by-step solution
Calculate now →Age Calculator
Calculate your exact age: years, months, days, days lived & countdown
Calculate now →Calendar Week Calculator
Current week number, convert dates to ISO weeks, all weeks of the year with German public holidays
Calculate now →Roman Numerals Converter
Convert Roman numerals — live in both directions, with breakdown, validation and a 1–100 chart
Calculate now →Volume Calculator
Calculate volume & surface area of cube, cuboid, cylinder, sphere, cone & pyramid in litres — plus circle and Pythagoras calculator with sketch and step-by-step solution
Calculate now →Currency Converter
Convert euros to dollars, Swiss francs, pounds, złoty & 25 more currencies: daily ECB reference rates, cross rates, a 90-day chart and a markup check
Calculate now →Online Calculator
Online calculator with order of operations, percent, brackets, memory, history and scientific functions
Calculate now →Understand Math with Step-by-Step Solutions
Whether it's the Rule of Three, percentages or fractions — our math calculators don't just show the result, they explain the complete solution path step by step. Perfect for students and anyone who needs math in everyday life.
All calculators are free, instantly usable and work directly in your browser — no sign-up, no tracking, full privacy.