Calculators
Fast, free calculators for everyday math, dates, percentages, and more.
Aspect Ratio Calculator
Work out aspect ratios and resize dimensions — simplify a size to 16:9, or find the missing width or height. In your browser.
CalculatorsPercentage Calculator
Three quick percentage calculations — X% of a value, what percent one number is of another, and percentage change.
CalculatorsAge Calculator
Calculate your exact age in years, months and days from a date of birth — plus total days lived. Free, in your browser.
CalculatorsDate Difference Calculator
Find the time between two dates in days, weeks, months and years — instantly and privately, in your browser.
CalculatorsDiscount Calculator
Calculate the sale price and amount saved after a percentage discount, or work out the discount percent from original and final prices — 100% in your browser, no upload.
CalculatorsGCD & LCM Calculator
Find the greatest common divisor and least common multiple of any list of integers instantly — runs 100% in your browser with no upload.
CalculatorsPrime Checker & Factorization
Instantly check whether a number is prime and see its prime factorization — runs 100% in your browser with no upload.
CalculatorsVAT Calculator
Add or remove a VAT, GST or sales-tax percentage to see the gross, net and tax amounts instantly — 100% in your browser, no upload.
CalculatorsCompound Interest Calculator
Estimate the future value and total interest of savings or an investment from a principal, annual rate, term and compounding frequency — 100% in your browser, no upload.
CalculatorsFraction Simplifier
Reduce any fraction to lowest terms and see it as a decimal and a mixed number, or convert a decimal like 0.75 back to a fraction — calculated 100% in your browser with no upload.
CalculatorsMargin & Markup Calculator
Turn cost and revenue into profit, profit margin % and markup %, or work out the revenue needed to hit a target margin — 100% in your browser, no upload.
CalculatorsStatistics Calculator
Paste a list of numbers to instantly get count, sum, mean, median, mode, min, max, range, quartiles (Q1/Q3), IQR, variance, and standard deviation — runs 100% in your browser with no upload.
CalculatorsFactorial, Permutations & Combinations Calculator
Compute n!, nPr and nCr exactly for any size of number — runs 100% in your browser with no upload.
CalculatorsQuadratic Equation Solver
Solve any quadratic equation ax² + bx + c = 0 and get the roots, discriminant, and vertex — runs 100% in your browser with no upload.
CalculatorsISO Week Number Calculator
Find the ISO 8601 week number, week-year, and day-of-year for any date — runs 100% in your browser with no upload.
CalculatorsCircle Calculator
Enter any one of a circle's radius, diameter, circumference, or area and instantly get the other three — runs 100% in your browser with no upload.
CalculatorsPythagorean Theorem Calculator
Find the missing side of a right triangle from any two sides using the Pythagorean theorem — runs 100% in your browser with no upload.
CalculatorsTime Ago Calculator
Turn any date and time into a human relative phrase like "3 hours ago" or "in 2 days" — runs 100% in your browser with no upload.
CalculatorsAdd or Subtract Days Calculator
Add or subtract days, weeks, months, or years from any date and see the resulting date and weekday — runs 100% in your browser with no upload.
CalculatorsLeap Year Checker
Instantly check whether any year is a leap year, see why, how many days it has, and the next leap years — runs 100% in your browser with no upload.
CalculatorsSlope Calculator (Two Points)
Find the slope, y-intercept, line equation y = mx + b, and angle from two points — runs 100% in your browser with no upload.
CalculatorsBusiness Days Calculator
Count the working days (Mon–Fri) and weekend days between two dates, inclusive of both endpoints — runs 100% in your browser with no upload.
CalculatorsDay of the Week Finder
Find out what day of the week any date falls on, plus its day-of-year and whether it is a weekend — runs 100% in your browser with no upload.
CalculatorsDistance & Midpoint Calculator
Calculate the straight-line distance and midpoint between two 2D points from their x and y coordinates — runs 100% in your browser with no upload.
CalculatorsFibonacci Sequence Generator & Nth Term Calculator
Generate the first N Fibonacci numbers or find the exact Nth term with BigInt precision — runs 100% in your browser with no upload.
CalculatorsProportion Calculator (a/b = c/d)
Solve a proportion a/b = c/d by entering any three values and leaving one blank — runs 100% in your browser with no upload.
CalculatorsDays in Month Calculator
Instantly find how many days are in any month of any year, with leap years handled automatically — runs 100% in your browser with no upload.
CalculatorsOhm's Law Calculator
Enter any two of voltage, current, resistance, or power and this Ohm's law calculator instantly finds the other two — runs 100% in your browser with no upload.
CalculatorsScientific Notation Converter
Convert any number to and from scientific and engineering notation instantly — runs 100% in your browser with no upload.
CalculatorsZodiac Sign Finder
Find your Western star sign and Chinese zodiac animal from any birth date — runs 100% in your browser with no upload.
CalculatorsGolden Ratio Calculator (Phi 1.618)
Enter the longer, shorter, or whole segment and instantly get all golden-ratio (phi = 1.618) values — runs 100% in your browser with no upload.
CalculatorsMoon Phase Calculator
Find the moon phase and approximate illumination percentage for any date — runs 100% in your browser with no upload.
CalculatorsWeighted Average Calculator
Enter value and weight pairs to instantly compute a weighted average and total weight — runs 100% in your browser with nothing uploaded.
CalculatorsLogarithm Calculator (log any base, ln, log10)
Calculate the logarithm of any number in any base, plus natural log (ln) and log base 10 — runs 100% in your browser with no upload.
CalculatorsNth Root Calculator
Calculate the square root, cube root, or any nth root of a number instantly — runs 100% in your browser with no upload.
CalculatorsArithmetic Sequence Calculator
List every term, find the Nth term, and compute the sum of an arithmetic sequence from its first term and common difference — runs 100% in your browser with no upload.
CalculatorsTime Duration Calculator (Add & Subtract HH:MM:SS)
Add and subtract time durations in HH:MM:SS or MM:SS, one per line with optional + or −, and get the running total instantly — runs 100% in your browser with no upload.
CalculatorsEaster Date Calculator
Find the exact date of Western (Gregorian) Easter Sunday for any year using the Meeus/Jones/Butcher algorithm — runs 100% in your browser with no upload.
CalculatorsGeometric Sequence Calculator
List every term, find the Nth term, and compute the sum of a geometric sequence from its first term and common ratio — runs 100% in your browser with no upload.
CalculatorsSimple Interest Calculator
Estimate the interest and total amount on a principal from an annual rate and a term in years, months or days using the simple interest formula — 100% in your browser, no upload.
CalculatorsTime Card Calculator
Enter clock-in and clock-out times with optional break minutes to get decimal hours worked per day and a weekly total — 100% in your browser, no upload.
CalculatorsJulian Day Number Converter
Convert any Gregorian calendar date to its astronomical Julian Day Number and back, instantly — runs 100% in your browser with no upload.
CalculatorsSignificant Figures Rounder
Round any number to a chosen number of significant figures instantly — runs 100% in your browser with no upload.
CalculatorsBMI Calculator
Calculate your Body Mass Index from height and weight in metric or imperial units, with your category and healthy weight range — 100% in your browser, no upload.
CalculatorsLoan & Mortgage Calculator
Calculate the monthly payment, total interest and a full amortization schedule for a fixed-rate loan or mortgage — 100% in your browser, no upload.
CalculatorsTip Calculator
Work out the tip, total and per-person amount for any bill, with quick 10–25% presets and bill splitting — 100% in your browser, no upload.
CalculatorsCalorie Calculator (TDEE & BMR)
Estimate your daily calorie needs — BMR, maintenance (TDEE) and weight-loss or gain targets — using the Mifflin–St Jeor equation, 100% in your browser.
CalculatorsGPA Calculator
Calculate your weighted grade point average on the 4.0 scale from each course's letter grade and credit hours — 100% in your browser, no upload.
CalculatorsSalary Calculator — Hourly ↔ Annual Pay Converter
Convert pay between hourly, daily, weekly, monthly and annual — set your own hours per week and weeks per year. Free, instant and 100% in your browser.
CalculatorsRunning Pace Calculator — min/km, min/mile & Finish Times
Enter a distance and time to get your pace per km and per mile, speed, and predicted 5K, 10K, half and full marathon finish times. Free, in your browser.
CalculatorsGrade Calculator — Test Score % and Final Grade Needed
Turn correct answers into a percentage and letter grade, or work out the score you need on the final to hit your target. Free, instant, in your browser.
CalculatorsFuel Cost Calculator — Trip Gas & Petrol Cost
Estimate the fuel cost of a trip from distance, fuel economy and price — miles or km, mpg, L/100km or km/L — and split it between passengers. Free, in your browser.
CalculatorsBody Fat Calculator — U.S. Navy Method
Estimate your body fat percentage from tape measurements using the U.S. Navy circumference method — metric or imperial. Free, private, 100% in your browser.
CalculatorsSleep Calculator — Bedtime & Wake-Up Time
Find the best time to sleep or wake based on 90-minute sleep cycles. Enter a time and get bedtime or wake-up suggestions. Free, in your browser.
CalculatorsElectricity Cost Calculator — Appliance Running Cost
Work out what an appliance costs to run per day, month and year from its wattage, hours of use and your electricity rate. Free, 100% in your browser.
CalculatorsPaint Calculator — How Much Paint You Need
Estimate how many gallons or litres of paint a room needs from wall size, doors, windows and coats. Metric or imperial, free, in your browser.
CalculatorsConcrete Calculator — Cubic Yards & Bags
Calculate concrete volume for a slab or footing in cubic yards, metres and feet, plus how many 40/60/80 lb bags you need. Free, in your browser.
CalculatorsPregnancy Due Date Calculator (Naegele’s Rule)
Estimate your pregnancy due date from your last menstrual period, and see how many weeks along you are. An estimate, not medical advice. In your browser.
CalculatorsSquare Footage Calculator — Area of a Room
Add up the square footage (and square metres) of one or more rooms, with an optional total cost per square foot. Free, in your browser.
CalculatorsTile Calculator — Tiles & Boxes Needed
Work out how many tiles and boxes you need for a floor or wall from the area, tile size and a waste allowance. Metric or imperial, in your browser.
CalculatorsIdeal Weight Calculator (Devine, Robinson, Miller, Hamwi)
Estimate ideal body weight from height and sex using four classic clinical formulas, plus the healthy BMI weight range. Free, in your browser.
CalculatorsUnit Price Calculator — Cost Per Unit & Best Value
Compare products by price per unit to find the best value. Enter each option’s price and amount; the cheapest per unit is highlighted. In your browser.
CalculatorsWater Intake Calculator — Daily Water Needs
Estimate how much water to drink a day from your weight, exercise and climate — in litres, ounces and cups. A general guide, in your browser.
CalculatorsOne-Rep Max (1RM) Calculator + Training Loads
Estimate your one-rep max from a weight and reps using the Epley and Brzycki formulas, with a percentage table of training loads. In your browser.
CalculatorsDog Age Calculator — Dog Years to Human Years
Convert your dog’s age to human years using a size-adjusted model and the 2019 epigenetic-clock formula. Free, in your browser.