All 110 Free Online Calculators
Fast, accurate calculators for math, percentages, finance, academic GPA, time duration, measurement conversions, social media, and everyday calculations.
Featured Calculators
A curated selection of high-utility calculators designed for speed, accuracy, and clear answers.
Percentage Calculator
Calculate percentages, percentage changes, increases, decreases, and reverse percentage values quickly.
Percentage Increase Calculator
Calculate the percentage increase between an original value and a new value, or find the new value after an increase.
Percentage Difference Calculator
Calculate the percentage difference between two values symmetrically using their arithmetic mean as the reference baseline.
Percentage Change Calculator
Calculate the percentage change between an original value and a new value, including percentage increases, decreases, and absolute difference.
Fraction Calculator
Add, subtract, multiply, and divide fractions, mixed numbers, and decimals with step-by-step simplification and visual fraction inputs.
GPA Calculator
Calculate high school and college cumulative GPA on a standard 4.0 unweighted scale, and check semester honors eligibility.
Grade Calculator
Calculate current class grades, weighted assignment scores, and final exam scores needed to pass.
Color Matcher
Identify an existing color and convert it across HEX, RGB, and HSL formats, then generate a matching complementary palette and tint/shade scale from it.
Universal Unit Converter
Convert length, weight, volume, area, temperature, speed, time, and digital data storage units instantaneously with clear conversion tables.
Length Converter
Convert meters, feet, inches, centimeters, kilometers, miles, yards, millimeters, and nautical miles with formulas and visual matrices.
Weight Converter
Convert kilograms, pounds, grams, ounces, metric tons, stones, and US tons with live unit comparison tables.
Height Converter
Convert human height between feet + inches, centimeters, meters, and total inches with visual height benchmarks.
Temperature Converter
Convert temperatures between Celsius (°C), Fahrenheit (°F), and Kelvin (K) with instant formula breakdowns.
Volume Converter
Convert liters, milliliters, US gallons, quarts, pints, cups, fluid ounces, tablespoons, and cubic meters.
Area Converter
Convert square meters, square feet, acres, hectares, square kilometers, square miles, and square yards.
Speed Converter
Convert speed between miles per hour (mph), kilometers per hour (km/h), meters per second (m/s), and knots.
Time Converter
Convert duration units from milliseconds, seconds, and minutes to hours, days, weeks, months, and years.
Data Storage Converter
Convert digital data sizes from bits and Bytes to Kilobytes, Megabytes, Gigabytes, Terabytes, and binary KiB/MiB/GiB.
Age Calculator
Calculate your exact age in years, months, days, weeks, hours, and minutes from your date of birth to any target date.
Date Difference Calculator
Calculate the exact difference between two dates in years, months, weeks, and total days with inclusive and exclusive counting.
Days Between Dates Calculator
Calculate the total number of days between any two calendar dates with instant inclusive and exclusive count breakdowns.
Date Calculator (Add / Subtract Days)
Add or subtract days, weeks, months, or years to or from any starting date with calendar-aware leap year and month-end rules.
Time Duration Calculator
Calculate duration and elapsed time between a start time and end time in hours, minutes, and seconds with midnight crossing support.
Weeks Calculator
Convert days to weeks, weeks to days, or calculate total weeks between two dates with remaining days breakdown.
Hours Calculator
Convert between hours, minutes, and seconds, including decimal-hour conversions for payroll and billing.
Simple Interest Calculator
Calculate simple interest, interest earned, and final accumulated balance over any time period using the standard I = P × R × T formula.
Compound Interest Calculator
Calculate compound interest growth over time with customizable compounding frequencies and regular monthly or annual contributions.
Loan Calculator
Calculate estimated monthly loan payments, total interest paid, and total cost with complete amortization schedule breakdown.
Payment Calculator
Calculate loan payments, principal balance, or loan terms based on interest rate and desired payment frequency.
Mortgage Calculator
Estimate total monthly mortgage payment including principal, interest, property taxes, home insurance, and HOA fees.
Tip Calculator
Calculate restaurant tip amounts, total bill, and split bill per person with quick percentage presets.
Discount Calculator
Calculate sale price and total money saved after applying percentage discounts with quick percentage preset buttons.
Sales Tax Calculator
Calculate sales tax amount and total purchase price, or extract pre-tax price from tax-inclusive totals.
Markup Calculator
Calculate selling price and markup amount from cost price and markup percentage, or reverse-calculate markup % from cost and retail price.
Profit Margin Calculator
Calculate gross profit margin percentage, net profit dollar amount, and markup percentage from revenue and cost.
Percentage Discount Calculator
Calculate the exact dollar amount and final price when a percentage discount is applied to a price — see precisely what any percent-off deal is worth.
Debt Payoff Calculator
Calculate time required to completely pay off credit cards or loans based on current balance, interest rate, and monthly payment.
Savings Calculator
Calculate compound interest growth on savings accounts with regular monthly or yearly deposits over time.
Investment Return Calculator
Calculate total gain and percentage return (ROI) on investments given initial amount, recurring contributions, and final portfolio value.
Hourly Rate Calculator
Calculate the minimum hourly rate you must charge as a freelancer to achieve your net annual income target.
Freelance Rate Calculator
Determine your ideal freelance hourly and day rates based on monthly target revenue and overhead.
Salary to Hourly Calculator
Convert annual, monthly, or weekly salaries into equivalent hourly wage rates.
Profit Calculator
Calculate gross profit, net profit, and profit margin percentage from revenue and operating costs.
Break-Even Calculator
Determine the exact sales volume and revenue required to cover fixed and variable costs.
ROI Calculator
Calculate return on investment (ROI) percentage and total financial return from gain and initial investment.
Social Media Engagement Rate Calculator
Calculate audience engagement rate across social platforms using likes, comments, shares, and follower count.
Instagram Engagement Rate Calculator
Calculate Instagram post and Reel engagement percentage based on likes, comments, and followers.
TikTok Engagement Rate Calculator
Calculate TikTok video engagement rate based on likes, comments, shares, and video views.
Creator Sponsorship Rate Calculator
Estimate sponsored post and brand deal rates for Instagram, TikTok, and YouTube creators.
Clothing Size Converter
Convert international clothing sizes across US, UK, EU, and AU size charts based on body measurements.
Women's Clothing Size Converter
Convert women's dresses, tops, jeans, and coats across US, UK, EU, and AU sizing charts.
Shoe Size Converter
Convert men's, women's, and kids' shoe sizes between US, UK, EU, CM, and foot length inches.
Bra Size Calculator
Calculate your accurate bra band and cup size using underbust and bust measurements in inches or cm.
Makeup Shade Matcher
Find your ideal makeup and foundation shade family based on skin depth and cool, warm, or neutral undertones.
Foundation Shade Matcher
Compare and match foundation shades across popular cosmetic brands using undertone and depth references.
Time Card Calculator
Calculate daily and total weekly work hours, break times, and overtime pay with a clean digital timesheet.
Work Hours Calculator
Calculate total work hours per day, week, month, and year with start time, end time, and break deductions.
Overtime Pay Calculator
Calculate regular pay, overtime pay, and total earnings using configurable overtime rate multipliers.
Pomodoro Technique Calculator
Calculate the total focus time, break duration, and estimated completion time for your Pomodoro study or work session.
Percentage of Time Calculator
Calculate what a specific percentage of a time duration equals in hours, minutes, and seconds.
Productivity Percentage Calculator
Measure work efficiency by comparing planned working hours against actual productive time spent.
Final Grade Calculator
Find out what score you need on your final exam to achieve your target overall class grade.
Weighted Grade Calculator
Calculate your current class grade using weighted categories (e.g. Homework 20%, Quizzes 30%, Exams 50%).
Exam Score Calculator
Calculate your percentage score, letter grade, and missed points from total test, quiz, or exam questions.
Study Time Calculator
Plan total study hours, daily study quotas, and subject allocations leading up to exam dates.
Semester Grade Calculator
Calculate your overall term or semester grade point average across multiple courses.
Paint Calculator
Calculate how many gallons or liters of paint you need for room walls after deducting doors and windows.
Flooring Calculator
Calculate total square footage and required flooring material including standard waste allowance percentages.
Tile Calculator
Calculate the exact number of tiles required for floors or backsplash walls based on tile size and area dimensions.
Room Area Calculator
Calculate square footage and square meters for rectangular, L-shaped, and triangular room spaces.
Room Volume Calculator
Calculate cubic feet, cubic meters, liters, and air volume for HVAC sizing and room capacity.
Electricity Cost Calculator
Calculate appliance power consumption in kWh and estimated monthly or annual electricity bill costs.
Water Usage Calculator
Estimate daily, weekly, and monthly water consumption in gallons and liters for showers, faucets, and appliances.
Average (Mean) Calculator
Calculate the arithmetic mean, sum, count, minimum, maximum, and range of any set of numbers.
Median Calculator
Find the middle number (median), mode, range, and sorted numerical sequence of any set of data.
Ratio Calculator
Simplify ratios to lowest terms, convert ratios to fractions and percentages, and solve equivalent ratios.
Proportion Calculator
Solve for the missing term X in proportions of the form A/B = C/D with cross-multiplication steps.
Prime Number Checker
Check whether an integer is prime or composite and view its complete factor list and prime factorization.
Factor Calculator
Find all integer factors, factor pairs, and prime factorization for any given positive integer.
Random Number Generator
Generate customizable true or pseudo-random integer sequences between specified minimum and maximum bounds.
Number Sequence Calculator
Calculate arithmetic and geometric sequence terms, the nth term value, and the sum of n terms.
Greatest Common Factor (GCF) Calculator
Find the greatest common factor (GCF / HCF) of two or more numbers using prime factorization or Euclidean algorithm.
Least Common Multiple (LCM) Calculator
Find the least common multiple (LCM) of two or more numbers with step-by-step formula and prime factor breakdown.
Color Picker & Matcher
Select colors, extract HEX, RGB, and HSL values, and match color combinations for design projects.
Color Contrast Checker (WCAG)
Check color contrast ratios against WCAG 2.1 accessibility guidelines for AA and AAA compliance.
Color Palette Generator
Generate harmonized color palettes including complementary, analogous, triadic, and monochromatic schemes.
Aspect Ratio Calculator
Calculate image and video aspect ratios, resize dimensions proportionally, and simplify aspect ratios.
PX to REM Converter
Convert pixel values to CSS root em (REM) units based on customizable base font sizes.
Countdown Calculator
Calculate the exact remaining time (days, hours, minutes, seconds) until a future event date.
Browse All Calculators
Comprehensive index of all available calculators grouped by functional domain.
Fraction Calculator
Add, subtract, multiply, and divide fractions, mixed numbers, and decimals with step-by-step simplification and visual fraction inputs.
Average (Mean) Calculator
Calculate the arithmetic mean, sum, count, minimum, maximum, and range of any set of numbers.
Median Calculator
Find the middle number (median), mode, range, and sorted numerical sequence of any set of data.
Ratio Calculator
Simplify ratios to lowest terms, convert ratios to fractions and percentages, and solve equivalent ratios.
Proportion Calculator
Solve for the missing term X in proportions of the form A/B = C/D with cross-multiplication steps.
Prime Number Checker
Check whether an integer is prime or composite and view its complete factor list and prime factorization.
Percentage Calculator
Calculate percentages, percentage changes, increases, decreases, and reverse percentage values quickly.
Percentage Increase Calculator
Calculate the percentage increase between an original value and a new value, or find the new value after an increase.
Percentage Difference Calculator
Calculate the percentage difference between two values symmetrically using their arithmetic mean as the reference baseline.
Percentage Change Calculator
Calculate the percentage change between an original value and a new value, including percentage increases, decreases, and absolute difference.
Percentage Decrease Calculator
Calculate percentage decrease and drop from an initial value to a lower new value.
GPA Calculator
Calculate high school and college cumulative GPA on a standard 4.0 unweighted scale, and check semester honors eligibility.
Grade Calculator
Calculate current class grades, weighted assignment scores, and final exam scores needed to pass.
Attendance Calculator
Calculate current class attendance percentage and number of future classes you can miss or must attend.
Final Grade Calculator
Find out what score you need on your final exam to achieve your target overall class grade.
Weighted Grade Calculator
Calculate your current class grade using weighted categories (e.g. Homework 20%, Quizzes 30%, Exams 50%).
Exam Score Calculator
Calculate your percentage score, letter grade, and missed points from total test, quiz, or exam questions.
Simple Interest Calculator
Calculate simple interest, interest earned, and final accumulated balance over any time period using the standard I = P × R × T formula.
Compound Interest Calculator
Calculate compound interest growth over time with customizable compounding frequencies and regular monthly or annual contributions.
Loan Calculator
Calculate estimated monthly loan payments, total interest paid, and total cost with complete amortization schedule breakdown.
Payment Calculator
Calculate loan payments, principal balance, or loan terms based on interest rate and desired payment frequency.
Mortgage Calculator
Estimate total monthly mortgage payment including principal, interest, property taxes, home insurance, and HOA fees.
Tip Calculator
Calculate restaurant tip amounts, total bill, and split bill per person with quick percentage presets.
Hourly Rate Calculator
Calculate the minimum hourly rate you must charge as a freelancer to achieve your net annual income target.
Freelance Rate Calculator
Determine your ideal freelance hourly and day rates based on monthly target revenue and overhead.
Salary to Hourly Calculator
Convert annual, monthly, or weekly salaries into equivalent hourly wage rates.
Hourly to Salary Calculator
Calculate equivalent annual, monthly, and weekly gross income from an hourly pay rate.
Commission Calculator
Calculate sales commission earnings and total compensation from sales volume and commission percentage rates.
Revenue Calculator
Calculate gross sales revenue based on unit price and total quantity sold.
Age Calculator
Calculate your exact age in years, months, days, weeks, hours, and minutes from your date of birth to any target date.
Date Difference Calculator
Calculate the exact difference between two dates in years, months, weeks, and total days with inclusive and exclusive counting.
Days Between Dates Calculator
Calculate the total number of days between any two calendar dates with instant inclusive and exclusive count breakdowns.
Date Calculator (Add / Subtract Days)
Add or subtract days, weeks, months, or years to or from any starting date with calendar-aware leap year and month-end rules.
Time Duration Calculator
Calculate duration and elapsed time between a start time and end time in hours, minutes, and seconds with midnight crossing support.
Weeks Calculator
Convert days to weeks, weeks to days, or calculate total weeks between two dates with remaining days breakdown.
Universal Unit Converter
Convert length, weight, volume, area, temperature, speed, time, and digital data storage units instantaneously with clear conversion tables.
Length Converter
Convert meters, feet, inches, centimeters, kilometers, miles, yards, millimeters, and nautical miles with formulas and visual matrices.
Weight Converter
Convert kilograms, pounds, grams, ounces, metric tons, stones, and US tons with live unit comparison tables.
Height Converter
Convert human height between feet + inches, centimeters, meters, and total inches with visual height benchmarks.
Temperature Converter
Convert temperatures between Celsius (°C), Fahrenheit (°F), and Kelvin (K) with instant formula breakdowns.
Volume Converter
Convert liters, milliliters, US gallons, quarts, pints, cups, fluid ounces, tablespoons, and cubic meters.
Clothing Size Converter
Convert international clothing sizes across US, UK, EU, and AU size charts based on body measurements.
Women's Clothing Size Converter
Convert women's dresses, tops, jeans, and coats across US, UK, EU, and AU sizing charts.
Men's Clothing Size Converter
Convert men's suit jackets, dress shirts, coats, and trousers across US, UK, and European standards.
Kids' Clothing Size Converter
Find the right children's and toddler clothing sizes based on age and height.
Shoe Size Converter
Convert men's, women's, and kids' shoe sizes between US, UK, EU, CM, and foot length inches.
Women's Shoe Size Converter
Convert women's heels, boots, and sneakers across US, UK, EU, Japan (CM), and foot length.
Makeup Shade Matcher
Find your ideal makeup and foundation shade family based on skin depth and cool, warm, or neutral undertones.
Foundation Shade Matcher
Compare and match foundation shades across popular cosmetic brands using undertone and depth references.
Beauty Measurement Converter
Convert beauty, cosmetic, and body measurements between millimeters, centimeters, inches, and feet.
Hair Length Converter
Convert hair extension lengths between inches and cm and map to descriptions like Shoulder, Mid-Back, or Waist.
Social Media Engagement Rate Calculator
Calculate audience engagement rate across social platforms using likes, comments, shares, and follower count.
Instagram Engagement Rate Calculator
Calculate Instagram post and Reel engagement percentage based on likes, comments, and followers.
TikTok Engagement Rate Calculator
Calculate TikTok video engagement rate based on likes, comments, shares, and video views.
YouTube Engagement Rate Calculator
Calculate YouTube channel and video engagement rate from likes, comments, and total views.
Creator Sponsorship Rate Calculator
Estimate sponsored post and brand deal rates for Instagram, TikTok, and YouTube creators.
Time Card Calculator
Calculate daily and total weekly work hours, break times, and overtime pay with a clean digital timesheet.
Work Hours Calculator
Calculate total work hours per day, week, month, and year with start time, end time, and break deductions.
Overtime Pay Calculator
Calculate regular pay, overtime pay, and total earnings using configurable overtime rate multipliers.
Pomodoro Technique Calculator
Calculate the total focus time, break duration, and estimated completion time for your Pomodoro study or work session.
Percentage of Time Calculator
Calculate what a specific percentage of a time duration equals in hours, minutes, and seconds.
Productivity Percentage Calculator
Measure work efficiency by comparing planned working hours against actual productive time spent.
Paint Calculator
Calculate how many gallons or liters of paint you need for room walls after deducting doors and windows.
Flooring Calculator
Calculate total square footage and required flooring material including standard waste allowance percentages.
Tile Calculator
Calculate the exact number of tiles required for floors or backsplash walls based on tile size and area dimensions.
Room Area Calculator
Calculate square footage and square meters for rectangular, L-shaped, and triangular room spaces.
Room Volume Calculator
Calculate cubic feet, cubic meters, liters, and air volume for HVAC sizing and room capacity.
Electricity Cost Calculator
Calculate appliance power consumption in kWh and estimated monthly or annual electricity bill costs.
Color Matcher
Identify an existing color and convert it across HEX, RGB, and HSL formats, then generate a matching complementary palette and tint/shade scale from it.
Color Picker & Matcher
Select colors, extract HEX, RGB, and HSL values, and match color combinations for design projects.
Color Converter (HEX / RGB / HSL)
Convert between HEX, RGB, and HSL color representations with precise visual feedback.
Color Contrast Checker (WCAG)
Check color contrast ratios against WCAG 2.1 accessibility guidelines for AA and AAA compliance.
Color Palette Generator
Generate harmonized color palettes including complementary, analogous, triadic, and monochromatic schemes.
Color Shade & Tint Generator
Generate lighter tints and darker shades for any base HEX color code.