Calculators
Free online math, finance, health, date & time, education, and construction calculators for percentages, loans, BMI, GPA, concrete, paint, and more. Instant results, no signup required.
Math Calculators
Percentage Calculator
Find a percentage of a number, discover what percent one value is of another, or calculate percent increase and decrease.
Open calculator →Average Calculator
Compute the arithmetic mean of any set of numbers — enter values separated by commas or spaces.
Open calculator →Median Calculator
Find the middle value of a data set — the median is robust against outliers unlike the mean.
Open calculator →Standard Deviation Calculator
Measure how spread out your data is — compute population standard deviation from any number list.
Open calculator →Random Number Generator
Generate a random integer between any minimum and maximum value, inclusive.
Open calculator →Fraction Calculator
Add, subtract, multiply, and divide fractions — results are automatically simplified to lowest terms.
Open calculator →Square Root Calculator
Calculate square roots, cube roots, and nth roots of any non-negative number.
Open calculator →Exponent Calculator
Raise any base to any power — compute exponents, including negative and fractional results.
Open calculator →Logarithm Calculator
Compute common logarithms (log₁₀), natural logarithms (ln), or logarithms with any custom base.
Open calculator →Roman Numeral Converter
Convert between Roman numerals and Arabic numbers — supports values from 1 to 3,999.
Open calculator →Number Base Converter
Convert numbers between decimal, binary, octal, and hexadecimal — essential for programming and computer science.
Open calculator →Ratio Calculator
Simplify ratios to lowest terms and solve for missing values in proportional relationships.
Open calculator →Proportion Calculator
Solve proportions of the form A/B = C/D — find the missing value in any proportional equation.
Open calculator →GCF Calculator
Find the greatest common factor (GCF) of two or more integers — also known as the greatest common divisor (GCD).
Open calculator →LCM Calculator
Find the least common multiple (LCM) of two or more integers — the smallest number divisible by all of them.
Open calculator →Scientific Notation Converter
Convert numbers to and from scientific notation — express very large or very small values compactly.
Open calculator →Basic Calculator
Free online basic calculator with memory, parentheses, keyboard support, and calculation history.
Open calculator →Scientific Calculator
Full scientific calculator with trigonometry, logarithms, powers, roots, factorial, and degree/radian modes.
Open calculator →Triangle Calculator
Solve any triangle from SSS, SAS, ASA, AAS, or SSA inputs. Find sides, angles, area, and more.
Open calculator →Circle Calculator
Enter radius, diameter, circumference, or area — calculate all circle properties including arc and sector.
Open calculator →Area Calculator
Calculate area for rectangles, triangles, circles, trapezoids, ellipses, and more with unit conversion.
Open calculator →Volume Calculator
Calculate volume and surface area for cubes, spheres, cylinders, cones, pyramids, and more 3D shapes.
Open calculator →Surface Area Calculator
Calculate total and lateral surface area for cubes, spheres, cylinders, cones, pyramids, and more.
Open calculator →Pythagorean Theorem Calculator
Enter any two sides of a right triangle to find the third using a² + b² = c² with step-by-step work.
Open calculator →Right Triangle Calculator
Solve right triangles from two sides or one side and one acute angle. Find all sides, angles, area, and altitude.
Open calculator →Slope Calculator
Find slope, distance, midpoint, and line equations from two points on a coordinate plane.
Open calculator →Distance Calculator
Calculate 2D or 3D distance and midpoint between two points.
Open calculator →Quadratic Formula Calculator
Solve ax² + bx + c = 0 with step-by-step work, vertex, and parabola graph.
Open calculator →Probability Calculator
Compute single-event probability, complements, and independent joint events as fractions, decimals, and percents.
Open calculator →Permutation & Combination Calculator
Calculate permutations nPr and combinations nCr with repetition options — order matters for permutations, not for combinations.
Open calculator →Z-Score Calculator
Standardize values with z = (x − μ) / σ, find probabilities from z-scores, and reverse-solve for raw scores.
Open calculator →Confidence Interval Calculator
Build confidence intervals for a population mean using sample mean, standard deviation, and sample size at 90%, 95%, or 99%.
Open calculator →Sample Size Calculator
Estimate required sample size for a proportion survey given confidence level, margin of error, and expected proportion.
Open calculator →P-Value Calculator
Find one-tailed or two-tailed p-values from z-scores or t-scores at common significance levels α = 0.01, 0.05, 0.10.
Open calculator →Statistics Calculator
Compute mean, median, mode, variance, standard deviation, quartiles, IQR, skewness, and more from any number list.
Open calculator →Factor Calculator
List all positive factors, factor pairs, count, and sum for any positive integer. Detects prime numbers.
Open calculator →Prime Factorization Calculator
Decompose any integer into prime factors with exponential notation, division steps, and primality check.
Open calculator →Matrix Calculator
Add, subtract, multiply, transpose, and find determinants and inverses of 2×2 and 3×3 matrices with step-by-step work.
Open calculator →Number Sequence Calculator
Detect arithmetic, geometric, and Fibonacci patterns from your terms. Find the next values, nth-term formulas, and partial sums.
Open calculator →Percent Error Calculator
Measure how far an experimental value deviates from theory. Also compute percent difference and percent change.
Open calculator →Rounding Calculator
Round to decimal places or significant figures. Compare half-up, half-even, ceiling, floor, and nearest integer methods.
Open calculator →Long Division Calculator
Divide with quotient, remainder, and decimal expansion. See step-by-step long division working like pencil-and-paper format.
Open calculator →Common Factor Calculator
Find all common factors, GCF, and LCM for two or more positive integers. Prime factorizations shown step by step.
Open calculator →Big Number Calculator
Add, subtract, multiply, divide, and exponentiate integers beyond JavaScript safe limits using arbitrary-precision arithmetic.
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Finance Calculators
Tip Calculator
Calculate tip amount, total bill, and per-person split for any check — choose tip percentage and number of diners.
Open calculator →Discount Calculator
Find the sale price and amount saved from any original price and discount percentage — perfect for shopping and sales.
Open calculator →Markup Calculator
Calculate selling price from cost and markup percentage — essential for retail pricing, wholesale, and product margins.
Open calculator →Profit Margin Calculator
Compute gross profit margin from revenue and cost — see what percentage of each sale dollar becomes profit.
Open calculator →Compound Interest Calculator
See how investments grow with compound interest — enter principal, rate, time, and compounding frequency.
Open calculator →Simple Interest Calculator
Calculate interest earned or owed using the simple interest formula — principal × rate × time.
Open calculator →Loan Calculator
Calculate monthly loan payments for auto, personal, or student loans — enter amount, interest rate, and term.
Open calculator →Mortgage Calculator
Estimate monthly mortgage payments for home purchases — enter loan amount, interest rate, and loan term in years.
Open calculator →Salary to Hourly Calculator
Convert annual salary to an hourly wage — enter yearly pay and hours worked per week to compare job offers.
Open calculator →Sales Tax Calculator
Calculate sales tax and total price from any subtotal and tax rate — useful for shopping, invoicing, and budgeting.
Open calculator →Savings Goal Calculator
Plan how much to save monthly to reach a financial goal — enter target amount, timeline, rate, and current savings.
Open calculator →Retirement Calculator
Project retirement savings growth from monthly contributions — enter current age, retirement age, savings, and return rate.
Open calculator →ROI Calculator
Calculate return on investment as a percentage — enter initial cost and final value to measure investment performance.
Open calculator →Credit Card Payoff Calculator
See how long it takes to pay off credit card debt — enter balance, APR, and monthly payment to find payoff timeline.
Open calculator →Inflation Calculator
See how inflation affects purchasing power over time — calculate future costs or what past dollars are worth today.
Open calculator →Break-Even Calculator
Find the break-even point for a business — enter fixed costs, variable cost per unit, and selling price per unit.
Open calculator →Debt Payoff Calculator
Plan paying off multiple debts using avalanche or snowball method — see payoff timeline and total interest saved.
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Health & Fitness Calculators
BMI Calculator
Calculate Body Mass Index from height and weight — see whether you fall in the underweight, normal, overweight, or obese range.
Open calculator →Calorie Calculator
Estimate daily calorie needs (TDEE) from age, sex, weight, height, and activity level — plan weight loss, maintenance, or gain.
Open calculator →BMR Calculator
Calculate basal metabolic rate — the calories your body burns at complete rest for breathing, circulation, and organ function.
Open calculator →Ideal Weight Calculator
Estimate a healthy target weight range from height and sex using Robinson, Devine, Miller, and Hamwi formulas.
Open calculator →Body Fat Calculator
Estimate body fat percentage using the U.S. Navy circumference method — enter height, neck, waist, and hip measurements.
Open calculator →Macro Calculator
Split daily calories into protein, carbohydrates, and fat grams — customize ratios for balanced, low-carb, or high-protein diets.
Open calculator →Water Intake Calculator
Estimate daily water needs from body weight and activity level — stay hydrated for exercise, heat, and everyday health.
Open calculator →Heart Rate Zone Calculator
Find your max heart rate and training zones — target fat burn, aerobic endurance, anaerobic threshold, and peak effort.
Open calculator →Pace Calculator
Convert between pace, speed, distance, and time for running or walking — plan race splits and training targets.
Open calculator →Pregnancy Due Date Calculator
Estimate your baby's due date from the first day of your last menstrual period using Naegele's rule (40-week gestation).
Open calculator →Ovulation Calculator
Predict fertile window and ovulation day from cycle length and last period — plan conception or track fertility awareness.
Open calculator →BAC Calculator
Estimate blood alcohol concentration from drinks consumed, body weight, sex, and time — understand impairment levels.
Open calculator →Sleep Cycle Calculator
Find optimal bedtimes and wake-up times aligned to 90-minute sleep cycles — wake refreshed between cycles, not mid-cycle.
Open calculator →Calories Burned Calculator
Estimate calories burned during exercise using MET values from the Compendium of Physical Activities — add multiple activities for a daily total.
Open calculator →Protein Calculator
Calculate daily protein needs based on body weight, age, activity level, and fitness goals — with meal splits and food source equivalents.
Open calculator →Healthy Weight Calculator
Find your healthy weight range from BMI 18.5–24.9 and compare ideal weight formulas — Devine, Robinson, Miller, and Hamwi.
Open calculator →Period Calculator
Predict your next periods, ovulation, fertile window, and PMS for the next 12 months — with a color-coded calendar.
Open calculator →Pregnancy Weight Gain Calculator
Calculate recommended pregnancy weight gain using IOM 2009 guidelines — week-by-week chart based on pre-pregnancy BMI.
Open calculator →Pregnancy Conception Calculator
Estimate conception date from due date or last period — find fertile windows and current pregnancy week.
Open calculator →Carbohydrate Calculator
Calculate daily carbohydrate needs from TDEE using Mifflin-St Jeor — moderate, low-carb, keto, and athlete approaches.
Open calculator →Fat Intake Calculator
Calculate daily fat intake from TDEE — general health, fat loss, muscle building, and keto approaches with fat-type breakdown.
Open calculator →Lean Body Mass Calculator
Calculate lean body mass from body fat percentage or using Boer, James, and Hume formulas — compare results and fat mass.
Open calculator →Calories Burned by Heart Rate Calculator
Estimate calories burned during exercise from heart rate using the Keytel 2005 formula — with intensity zones and max HR.
Open calculator →One Rep Max Calculator
Estimate your one-rep max (1RM) from submaximal weight and reps using Epley, Brzycki, Lombardi, and other formulas.
Open calculator →Target Heart Rate Calculator
Find your target heart rate zones from age using the simple max-HR method or optional Karvonen formula with resting HR.
Open calculator →Body Type Calculator
Determine frame size, women's body shape, or men's somatotype from wrist, height, and body measurements.
Open calculator →GFR Calculator
Estimate glomerular filtration rate (eGFR) from serum creatinine, age, and sex using CKD-EPI 2021 and MDRD equations.
Open calculator →Body Surface Area Calculator
Calculate body surface area (BSA) in m² from height and weight using Du Bois, Mosteller, Haycock, and Boyd formulas.
Open calculator →Army Body Fat Calculator
Calculate body fat percentage using the US Army AR 600-9 tape method and check pass/fail against age-based standards.
Open calculator →Overweight Calculator
See how much you are over or under a healthy weight, BMI class, calorie deficit target, and weeks to goal.
Open calculator →Conception Calculator
Track ovulation, fertile window, peak fertility, implantation, two-week wait, and pregnancy test dates across three cycles.
Open calculator →WW Points Calculator
Estimate SmartPoints-style values from calories, saturated fat, protein, and sugar with a reference food table.
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Date & Time Calculators
Age Calculator
Calculate exact age in years, months, and days from a birth date — see how many days you have lived and your next birthday.
Open calculator →Date Difference Calculator
Find the exact number of days, weeks, months, and years between any two calendar dates — inclusive or exclusive counting.
Open calculator →Day of Week Calculator
Find what day of the week any date falls on — past, present, or future — using perpetual calendar logic.
Open calculator →Add/Subtract Days Calculator
Add or subtract any number of days from a date to find the resulting calendar date — handles month and year boundaries automatically.
Open calculator →Working Days Calculator
Count business days between two dates or add working days to a start date — exclude weekends and optional holidays.
Open calculator →Weeks Calculator
Convert between weeks and days, or find the date a given number of weeks from any start date — ideal for pregnancy and project planning.
Open calculator →Time Duration Calculator
Calculate elapsed time between two clock times on the same or consecutive days — get hours, minutes, and seconds.
Open calculator →Countdown Calculator
Count down to any future date and time — see days, hours, minutes, and seconds remaining until your event or deadline.
Open calculator →Time Zone Converter
Convert any date and time between time zones — schedule international meetings without missing daylight saving shifts.
Open calculator →Unix Timestamp Converter
Convert Unix epoch timestamps (seconds or milliseconds) to human-readable dates and back — essential for developers and log analysis.
Open calculator →Months Calculator
Add or subtract calendar months from a date, or find the number of full months between two dates — handles month-end edge cases.
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Education Calculators
GPA Calculator
Calculate your semester GPA from course grades and credit hours — enter letter grades or percentages for an instant weighted average.
Open calculator →Cumulative GPA Calculator
Combine your current cumulative GPA with a new semester's grades to project your updated overall GPA across all completed credits.
Open calculator →Grade Calculator
Compute your current course grade from weighted assignments — enter scores and category weights to see your percentage and letter grade.
Open calculator →Weighted Grade Calculator
Calculate weighted averages across multiple graded categories — verify that weights total 100% and see your combined percentage and letter grade.
Open calculator →Test Score Calculator
Find the score you need on remaining questions or sections to hit your target grade — ideal for exams with known point totals.
Open calculator →Final Grade Calculator
Find the final exam score you need to earn your desired course grade — enter your current average and the final's weight percentage.
Open calculator →College GPA to Percentage Converter
Convert between U.S. 4.0 GPA and percentage grades — useful for international applications, transcripts, and cross-system comparisons.
Open calculator →Words Per Page Calculator
Estimate page counts from word totals — adjust for font, font size, and line spacing to match MLA, APA, and school essay requirements.
Open calculator →Reading Time Calculator
Estimate how long it takes to read or speak a document — enter word count or paste text for instant reading and presentation time.
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Construction & Home Calculators
Square Footage Calculator
Calculate area in square feet and square meters from length and width — essential for flooring, paint, tile, and landscaping estimates.
Open calculator →Concrete Calculator
Estimate concrete volume in cubic feet and cubic yards for slabs, columns, and stairs — includes 60 lb and 80 lb bag counts.
Open calculator →Paint Calculator
Estimate gallons of paint needed for walls and ceilings — accounts for doors, windows, coats, and standard coverage rates.
Open calculator →Tile Calculator
Calculate how many tiles you need for any floor or wall area — includes grout gap and customizable waste percentage.
Open calculator →Flooring Calculator
Estimate flooring material and cost for hardwood, laminate, vinyl, or carpet — includes 10% waste factor and price ranges.
Open calculator →Electricity Cost Calculator
Estimate daily, monthly, and yearly electricity costs for any appliance — enter watts, usage hours, and your kWh rate.
Open calculator →Fence Calculator
Estimate fence posts, rails, pickets, and panels from perimeter, height, and spacing — plan wood or vinyl fencing projects.
Open calculator →Gravel & Mulch Calculator
Calculate cubic yards and tons of gravel, mulch, sand, or topsoil from area and depth — plan landscaping and driveway projects.
Open calculator →Roofing Calculator
Calculate roof area, squares, and shingle bundles from footprint dimensions and pitch — account for slope on gable and hip roofs.
Open calculator →Wallpaper Calculator
Estimate wallpaper rolls needed for any room — accounts for doors, windows, roll dimensions, and pattern repeat matching.
Open calculator →BTU Calculator
Estimate heating and cooling BTU requirements from room size, insulation, climate, and windows — size HVAC and space heaters correctly.
Open calculator →Carpet Calculator
Calculate carpet and padding square footage for one or two room sections — includes 10% waste and cost estimates.
Open calculator →Staircase Calculator
Calculate stair rise, run, tread depth, and stringer length from total rise and run — design safe, code-compliant staircases.
Open calculator →Brick Calculator
Estimate bricks and mortar bags for any wall — enter wall dimensions, brick size, and mortar joint thickness.
Open calculator →Drywall Calculator
Estimate drywall sheets, joint compound, and tape for any room — accounts for doors, windows, and optional ceiling coverage.
Open calculator →Soil Calculator
Calculate garden soil, topsoil, or fill volume for rectangular and circular beds — results in cubic feet, yards, and bags.
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