Free Online Calculators
& Converters
Fast, accurate tools for math, science, health, finance, date & time, and unit conversions — just one click, no sign-up.
Scientific Calculator
A full-featured scientific calculator — type expressions or use the buttons below.
Popular Tools
Percentage Calculator
Calculate percentages quickly.
Age Calculator
Find your exact age from your birthdate.
GCF Calculator
Greatest common factor of two numbers.
Days Between Dates
Count exact days between any two dates.
Meters to Feet
Convert meters to feet instantly.
Kg to Pounds
Convert kilograms to pounds.
Celsius to Fahrenheit
Convert temperature units instantly.
Binary to Decimal
Convert binary numbers to decimal.
Mean Calculator
Find the arithmetic mean of a data set.
Slope Calculator
Calculate the slope between two points.
Quadratic Calculator
Solve quadratic equations (ax²+bx+c=0).
Fraction Calculator
Add, subtract, multiply, divide fractions.
Calculator Categories
View all →Math Calculators
Percentages, fractions, GCF, LCM, rounding, scientific notation, exponents, and more.
47 tools
Statistics Calculators
Mean, median, mode, range, standard deviation, variance, z-score, percentile, quartile, IQR.
19 tools
Date & Time Calculators
Age, date difference, business days, hours, time duration, sleep, overtime.
33 tools
Algebra Calculators
Slope, distance formula, quadratic equation, linear equation, vertex, factoring.
14 tools
Finance Calculators
Profit margin, markup, discount, CAGR, break-even, compound interest.
20 tools
Health Calculators
BMR, TDEE, ideal weight, body fat, calorie, pace, heart rate.
20 tools
Physics Calculators
Velocity, acceleration, force, energy, waves, density, ideal gas law.
41 tools
Geometry Calculators
Area, perimeter, volume, surface area for 2D and 3D shapes.
27 tools
Construction Calculators
Concrete, square footage, gravel, paint, tile, roofing, mulch, stairs.
21 tools
Electrical Calculators
Ohm's law, watts, amps, volts, kWh, resistor color code, LED power.
17 tools
Converter Categories
View all →Length Converter
Meters, feet, inches, kilometers, miles, yards, centimeters.
13 tools
Weight Converter
Kilograms, pounds, grams, ounces, tons.
10 tools
Temperature Converter
Celsius, Fahrenheit, Kelvin conversions.
6 tools
Speed Converter
MPH, KPH, meters per second, knots.
6 tools
Area Converter
Square feet, square meters, acres, hectares.
8 tools
Volume Converter
Liters, gallons, cups, milliliters, ounces, tablespoons.
9 tools
Time Converter
Seconds, minutes, hours, days, weeks, years.
15 tools
Number System Converter
Binary, decimal, hexadecimal, octal, Roman numerals, words.
19 tools
Data Converter
Megabytes, gigabytes, terabytes, kilobytes, Mbps.
9 tools
Pressure Converter
PSI, Bar, kilopascals (kPa), atmospheres.
7 tools
Energy Converter
Joules, calories, kilowatt-hours, BTU.
6 tools
Power Converter
Watts, kilowatts, horsepower (HP).
5 tools
Force Converter
Newtons, pound-force, kilonewtons.
4 tools
Angle Converter
Degrees, radians, gradians.
4 tools
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