Free Online Calculators
4,220+ fast, accurate calculators for math, finance, health, science, and everyday life. No signup required.
+Math Calculators
View all 336 →Percentage Calculator
Free online percentage calculator. Find percentages, percentage change, percentage difference, and more. Fast, accurate, no signup required.
MathFraction Calculator
Free fraction calculator. Add, subtract, multiply, and divide fractions. Simplify fractions and convert between fractions and decimals.
MathStandard Deviation Calculator
Free standard deviation calculator. Calculate mean, variance, and standard deviation for any dataset. Supports population and sample statistics.
MathVolume Calculator
Free volume calculator. Calculate volume of a box, cylinder, sphere, and cone. Convert between gallons, liters, and cubic feet.
MathRandom Number Generator
Free random number generator. Generate random numbers within any range. Perfect for lotteries, games, decision making, and statistics.
MathProbability Calculator
Free probability calculator. Calculate probability of events, combinations, permutations, and coin flip odds.
MathScientific Calculator
Free online scientific calculator. Calculate trigonometric functions, logarithms, powers, roots, and factorials instantly.
MathQuadratic Equation Calculator
Free quadratic equation calculator. Solve ax² + bx + c = 0 and find roots, vertex, discriminant, and axis of symmetry.
MathRatio Calculator
Free ratio calculator. Solve proportions, simplify ratios, and scale ratios up or down. Perfect for recipes, maps, and math problems.
MathPythagorean Theorem Calculator
Free Pythagorean theorem calculator. Find the missing side of a right triangle. Calculate hypotenuse or leg length from two known sides.
MathAverage Calculator
Free average calculator. Calculate the mean, median, mode, and range of a set of numbers quickly and easily.
MathLCM & GCD Calculator
Free LCM and GCD calculator. Find the Least Common Multiple and Greatest Common Divisor of two or more numbers.
Math$Finance Calculators
View all 953 →Compound Interest Calculator
Free compound interest calculator. See how your savings or investments grow over time with compound interest. Compare different rates and time periods.
FinanceMortgage Calculator
Free mortgage calculator. Estimate monthly mortgage payments, total interest, and amortization for your home loan. Compare different rates and terms.
FinanceLoan Calculator
Free loan calculator. Calculate monthly payments, total interest, and payoff schedule for any loan — car, personal, or student loans.
FinanceSalary Calculator
Free salary calculator. Convert between hourly, weekly, monthly, and annual pay. Estimate take-home pay after taxes.
FinanceROI Calculator
Free ROI (Return on Investment) calculator. Calculate investment returns, ROI percentage, and annualized ROI.
FinanceInflation Calculator
Free inflation calculator. See how purchasing power changes over time. Calculate the future value of money adjusted for inflation.
FinancePaycheck Calculator
Free paycheck calculator. Estimate your take-home pay after federal and state taxes, Social Security, and Medicare deductions.
FinanceTax Calculator
Free income tax calculator. Estimate your federal and state income tax for the current year. See your effective tax rate and tax bracket.
FinanceRetirement Calculator
Free retirement calculator. Estimate how much you need to save for retirement and project your retirement savings growth over time.
FinanceCar Loan Calculator
Free car loan calculator. Calculate monthly car payments, total interest, and compare auto loan options for new or used vehicles.
FinanceDown Payment Calculator
Free down payment calculator. Calculate how much you need for a house down payment and see how different down payment amounts affect your mortgage.
FinanceDebt Payoff Calculator
Free debt payoff calculator. Calculate how long it will take to pay off your debt and how much interest you'll pay. Compare payoff strategies.
FinanceHHealth Calculators
View all 554 →BMI Calculator
Free Body Mass Index (BMI) calculator. Calculate your BMI using metric or imperial units. Understand your BMI category and what it means for your health.
HealthCalorie Calculator
Free calorie calculator. Estimate your daily calorie needs (TDEE) based on age, gender, height, weight, and activity level. Plan for weight loss or gain.
HealthPace Calculator
Free running pace calculator. Calculate pace, speed, finish time, or distance for running, cycling, and walking.
HealthIdeal Weight Calculator
Free ideal weight calculator. Find your ideal body weight using multiple medical formulas (Devine, Robinson, Miller, Hamwi).
HealthBody Fat Calculator
Free body fat calculator. Estimate your body fat percentage using the US Navy method with waist, neck, and hip measurements.
HealthPregnancy Due Date Calculator
Free pregnancy due date calculator. Estimate your due date, conception date, and pregnancy milestones based on your last menstrual period.
HealthSleep Calculator
Free sleep calculator. Find the best time to go to sleep or wake up based on 90-minute sleep cycles. Wake up feeling refreshed.
HealthHeart Rate Zone Calculator
Free heart rate zone calculator. Find your target heart rate zones for fat burn, cardio, and peak performance based on age and resting heart rate.
HealthWater Intake Calculator
Free water intake calculator. Find out how much water you should drink per day based on your weight, activity level, and climate.
HealthProtein Calculator
Free protein intake calculator. Calculate how many grams of protein you need daily based on your weight, activity level, and fitness goals.
HealthMacro Calculator
Free macro calculator. Calculate your ideal macronutrient split (protein, carbs, fat) based on calories, body weight, and fitness goals.
HealthBAC Calculator
Free blood alcohol content calculator. Estimate your BAC based on drinks consumed, body weight, gender, and time elapsed.
Health~Everyday Calculators
View all 1534 →Age Calculator
Free online age calculator. Calculate your exact age in years, months, and days from your date of birth. Find out how many days old you are.
EverydayTip Calculator
Free tip calculator. Calculate how much to tip at restaurants, split the bill between friends, and figure out the total cost including tip.
EverydayGPA Calculator
Free GPA calculator. Calculate your Grade Point Average for college or high school. Supports letter grades and credit hours.
EverydayDiscount Calculator
Free discount calculator. Calculate sale prices, savings, and discount percentages. Perfect for shopping, sales tax, and price comparisons.
EverydaySquare Footage Calculator
Free square footage calculator. Calculate area in square feet for rooms, homes, flooring, and landscaping. Supports rectangular, circular, and triangular shapes.
EverydayDate Calculator
Free date calculator. Add or subtract days, weeks, or months from a date. Find the date after a specific number of days.
EverydayFuel Cost Calculator
Free fuel cost calculator. Estimate gas cost for a trip based on distance, fuel efficiency, and gas price.
EverydayElectricity Cost Calculator
Free electricity cost calculator. Estimate how much an appliance costs to run per day, month, and year based on wattage and electricity rate.
EverydayRent Split Calculator
Free rent split calculator. Split rent fairly by room size, income, or equally among roommates.
EverydayGrade Calculator
Free grade calculator. Calculate your weighted grade, find what you need on a final exam, and convert between grade formats.
EverydayConcrete Calculator
Free concrete calculator. Calculate how many bags or cubic yards of concrete you need for slabs, footings, columns, and stairs.
EverydayPaint Calculator
Free paint calculator. Calculate how much paint you need for walls, ceilings, and rooms. Estimate gallons and cost for your painting project.
EverydayAScience Calculators
View all 516 →Speed Distance Time Calculator
Free speed, distance, time calculator. Solve for any variable given the other two. Supports mph, km/h, and m/s.
ScienceSubnet Calculator
Free subnet calculator. Calculate network address, broadcast address, host range, and number of usable hosts from IP address and CIDR notation.
ScienceOhm's Law Calculator
Free Ohm's Law calculator. Calculate voltage, current, resistance, and power for any electrical circuit.
ScienceForce Calculator (F = ma)
Free force calculator. Calculate force, mass, or acceleration using Newton's second law F = ma.
ScienceDensity Calculator
Free density calculator. Calculate density, mass, or volume using the formula ρ = m/V. Includes common material densities.
ScienceEnergy Calculator
Free energy calculator. Calculate kinetic energy, potential energy, and work done. Convert between energy units (joules, calories, kWh).
ScienceMomentum Calculator
Free momentum calculator. Calculate linear momentum (p = mv) and impulse for physics problems.
ScienceAcceleration Calculator
Free acceleration calculator. Calculate acceleration from velocity change and time, or from force and mass.
ScienceWavelength Calculator
Free wavelength calculator. Calculate wavelength, frequency, or wave speed. Convert between Hz, kHz, MHz, and GHz.
SciencepH Calculator
Free pH calculator. Calculate pH from hydrogen ion concentration, convert between pH and pOH, and determine acidity or alkalinity.
ScienceWind Chill Calculator
Free wind chill calculator. Calculate the wind chill temperature index from air temperature and wind speed.
ScienceHeat Index Calculator
Free heat index calculator. Calculate the heat index (feels-like temperature) from air temperature and relative humidity.
ScienceRConversion Calculators
View all 327 →Unit Converter
Free unit converter. Convert between metric and imperial units for length, weight, and temperature. Instant results, no signup required.
ConversionTime Zone Converter
Free time zone converter. Convert time between any two time zones. See what time it is in other cities around the world.
ConversionBinary / Hex / Decimal Converter
Free number base converter. Convert between binary, decimal, hexadecimal, and octal number systems instantly.
ConversionCooking Measurement Converter
Free cooking measurement converter. Convert between cups, tablespoons, teaspoons, milliliters, ounces, and grams for cooking and baking.
ConversionColor Converter
Free color converter. Convert between HEX, RGB, and HSL color formats. Preview colors and get CSS values.
ConversionData Storage Converter
Free data storage converter. Convert between bytes, KB, MB, GB, TB, and PB. Understand file sizes and storage capacity.
ConversionShoe Size Converter
Free shoe size converter. Convert between US, UK, EU, and CM shoe sizes for men, women, and children.
ConversionSpeed Converter
Free speed converter. Convert between mph, km/h, m/s, knots, and Mach number instantly.
ConversionAngle Converter
Free angle converter. Convert between degrees, radians, gradians, and turns. Calculate arc length and sector area.
ConversionArea Converter
Free area converter. Convert between square feet, square meters, acres, hectares, and square miles.
ConversionPressure Converter
Free pressure converter. Convert between PSI, bar, atm, Pa, kPa, mmHg, and torr for engineering and science.
ConversionWeight Converter
Free weight converter. Convert between kilograms, pounds, ounces, grams, stone, and tons instantly.
Conversion