Free Math Tools & Calculators
Free online math tools for students, teachers and professionals. Calculate percentages, convert number bases, compute compound interest, roll dice and more. Every calculator works instantly in your browser — no app required.
20 math tools · No signup · Instant results
Percentage Calculator
Calculate percentages, percentage of a number, percentage change, percentage increase/decrease and what percentage one number is of another.
Percentage Change Calculator
Calculate the percentage change between two values. Shows increase or decrease with the exact percentage and difference.
Number Base Converter
Convert between binary, octal, decimal and hexadecimal number systems. Essential for computer science and programming.
Numbers to Words
Convert any number into written words. Handles integers, decimals and large numbers. Useful for cheques, invoices and legal documents.
Unit Converter
Convert between hundreds of measurement units across length, weight, volume, area, speed, energy and more.
Temperature Converter
Convert between Celsius, Fahrenheit and Kelvin with formula explanations. Includes common reference temperatures.
Length Calculator
Convert between metres, centimetres, inches, feet, yards, kilometres and miles. Metric and imperial conversions.
Weight Calculator
Convert between kilograms, pounds, stones, ounces, grams and tonnes. Covers everyday and scientific units.
Area Calculator
Convert between square metres, square feet, acres, hectares and more. Useful for property, gardening and construction.
Data Size Calculator
Convert between bytes, kilobytes, megabytes, gigabytes, terabytes and petabytes. Supports SI and binary units.
Energy Converter
Convert between joules, calories, kilocalories, kilowatt-hours, BTU and more. Physics and nutrition calculations.
Pressure Converter
Convert between Pascal, bar, PSI, atmospheres, mmHg and torr. Covers engineering, weather and medical applications.
Grade Calculator
Calculate your overall grade from weighted assignments. Add individual grades with their weights and see your current average.
Compound Interest Calculator
Calculate compound interest over time. See how investments grow with monthly or annual compounding. Includes visual charts.
Compound Interest Visualiser
Interactive visualisation of compound interest growth. See the power of compounding over 1, 5, 10, 20 and 30 years.
Inflation Calculator
Calculate the real value of money over time. See how inflation erodes purchasing power across decades.
Random Number Generator
Generate random numbers within any range. Use for probability experiments, sampling, games and decision making.
Dice Roller
Roll virtual dice — D4, D6, D8, D10, D12, D20 and custom-sided dice. Roll multiple dice and see totals.
Coin Flip Simulator
Flip a virtual coin for 50/50 decisions. Track results over multiple flips to explore probability.
Timestamp Calculator
Convert Unix timestamps to dates and dates to timestamps. Calculate the difference between two timestamps.
Quick Percentage Formulas
What is X% of Y? — Multiply Y by X/100. Example: 15% of 200 = 200 x 0.15 = 30
X is what % of Y? — Divide X by Y and multiply by 100. Example: 30 is what % of 200? = (30/200) x 100 = 15%
Percentage change — ((New - Old) / Old) x 100. Example: 200 to 250 = ((250-200)/200) x 100 = 25% increase
Skip the mental maths — use our Percentage Calculator instead.
Toolpile — free math tools, no nonsense. Browse all 194 tools