Calculators

Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) with the Mifflin-St Jeor equation

Estimate how much any appliance costs to run. Enter wattage, daily usage hours, and your electricity rate to see daily, monthly, and yearly energy costs.

Solve any quadratic equation ax² + bx + c = 0 instantly. Get real and complex roots, the discriminant, vertex, and a parabola graph — with step-by-step working.

Calculate screen pixels per inch (PPI), dot pitch, and total pixels from resolution and diagonal size. Supports inch and cm input — 100% in-browser.

Calculate percentages, increases, decreases, and differences. Four calculation modes for all your percentage needs.

Free BMI calculator to check your Body Mass Index. Calculate BMI instantly with metric or imperial units. Get health category classification and BMI chart.

Calculate your 5 training heart rate zones from age and resting pulse. Supports percent-of-max-HR and Karvonen heart rate reserve methods.

Calculate your weighted course grade from assignments and exams, or find the score you need on your final exam to reach a target grade. Includes letter grade and GPA conversion.

Calculate your exact age in years, months, days, hours, minutes, and seconds

Calculate and convert aspect ratios for images and videos

Free significant figures calculator. Count sig figs in any number, round to N significant figures, and perform arithmetic with correct sig-fig rounding rules. 100% client-side.

Analyze your disk space usage, track storage consumption, and calculate free space percentage with this free online tool.

Advanced scientific calculator with trigonometric functions, logarithms, powers, roots, factorial, and memory. Supports deg/rad modes with calculation history.

Calculate time durations, add or subtract time intervals, and convert between time units. Perfect for project management, billing, and time tracking.

Calculate fractions with ease. Add, subtract, multiply, and divide fractions.

Calculate your semester and cumulative GPA on the 4.0 scale. Add courses with credit hours and letter grades, combine with prior credits, and see Latin honors instantly.

Calculate your daily calorie needs using the Mifflin-St Jeor equation. Estimate BMR, TDEE, and calorie targets for weight loss, maintenance, and weight gain.

Free body fat calculator using the U.S. Navy method. Enter your height, neck, waist, and hip measurements to get your body fat percentage, fat mass, and lean body mass. Supports metric and imperial units for men and women.

Calculate mean, median, mode, range, sum, min, max, variance, standard deviation, quartiles, and more from any list of numbers. A free, fast statistics tool that runs entirely in your browser.

Calculate the best time to sleep or wake up using 90-minute sleep cycles

Free running pace calculator. Find your pace, finish time, or distance, with speed in km/h and mph and predicted splits for 5K, 10K, half marathon, and marathon. 100% client-side.

Calculate radioactive decay and exponential decay. Solve for remaining quantity, initial amount, half-life, or elapsed time with step-by-step formulas. Includes isotope presets and a decay timeline.

Calculate permutations (nPr) and combinations (nCr) with or without repetition. Exact arbitrary-precision results, formulas, and step-by-step working.

Estimate concrete volume and the number of pre-mixed bags you need for slabs, footings, columns, and post holes. Supports imperial and metric units, a waste factor, and a cost estimate.

Calculate your estimated due date (EDD) using Naegele’s rule. Estimate from your last menstrual period, conception date, or ultrasound scan. Track gestational age, trimester, and key milestones.

Find the Greatest Common Factor (GCF) and Least Common Multiple (LCM) of two or more numbers with prime factorization breakdown.

Decode resistor values from 4, 5, or 6 color bands, or reverse-look-up the bands from an ohm value. Supports tolerance and temperature coefficient per IEC 60062.

Calculate the volume of 3D shapes — box, cube, cylinder, sphere, cone, and pyramid — with instant unit conversions.

Free online surface area calculator for cube, box, cylinder, sphere, cone, and pyramid. Get results in cm2, m2, in2, and ft2 with formulas shown. 100% client-side.

Free online Ohm's Law calculator. Enter any two of voltage, current, resistance, or power and instantly get the remaining values with step-by-step derivations.

Free online heat index calculator. Enter air temperature and relative humidity to get the "feels-like" apparent temperature using the NWS Rothfusz formula. Supports Fahrenheit and Celsius with a color-coded heat safety level.

Free online wind chill calculator. Enter air temperature and wind speed to get the cold-weather “feels-like” temperature using the NWS and Environment Canada wind chill formula. Supports °F/°C and mph/km/h with a color-coded frostbite risk level.

Estimate how long a file or app will take to download based on its size and your internet connection speed.

Plot mathematical functions on an interactive canvas with zoom, pan, and multi-function support.

Estimate your daily water intake based on body weight, exercise, climate, and special conditions.

Factor any integer into prime factors with exponents, find divisors, and check if prime

Split a restaurant or group bill fairly among any number of people, with tips and tax

Calculate musical note frequencies from a reference pitch. Convert between note names, MIDI numbers, and Hertz using equal temperament tuning.

Reduce any width and height to its simplest aspect ratio like 16:9.

Add, subtract, multiply, transpose matrices, and compute determinants and inverses. Free, client-side linear algebra calculator.

Compute the union, intersection, difference, and symmetric difference of two lists with instant cardinality, subset, and equality checks.

Estimate your annual CO2 emissions from transport, home energy, and diet

Calculate standard deviation, variance, coefficient of variation, standard error, skewness, and kurtosis from any list of numbers. Free, fast, and runs entirely in your browser.

Solve triangles from sides, angles, or base and height.

Calculate the real cost of a meeting from attendees, hourly rate or salary, and duration

Size air conditioner capacity in BTU/h, kW, and tons from room dimensions, ceiling height, insulation, sun exposure, climate, and occupancy.

Calculate estimated completion time (ETA) from a start time and duration. Timezone-aware results with countdown, ISO 8601, and Unix timestamp output.

Estimate your ideal body weight using the Devine, Hamwi, Robinson, and Miller formulas. Free online IBW calculator with metric and imperial unit support.

Solve and minimize Boolean expressions on 2-4 variable Karnaugh maps with grouped prime implicants.

Calculate probabilities for normal, binomial, and Poisson distributions plus Bayes theorem. Compute PDF, CDF, PMF, cumulative probabilities, z-scores, and posterior probability. Free, fast, and runs entirely in your browser.

Calculate the molar mass (molecular weight) of any chemical formula using the full periodic table of atomic weights. Supports parentheses groups, hydrates, and multi-element compounds with a complete mass percent breakdown. Free, fast, and runs entirely in your browser.

Estimate your one-rep max (1RM) from weight and reps using six proven formulas, plus a percentage-based training chart.

Add, subtract, multiply, and divide complex numbers (a + bi). Compute modulus, argument, conjugate, reciprocal, and square with instant results.

Free online Impedance Calculator. Compute AC impedance of series and parallel RLC circuits from resistance, inductance, capacitance, and frequency. Get magnitude, phase angle, and reactances. 100% client-side.

Recalculate recipe ingredient amounts for a different number of servings with smart rounding.

Convert dog age into human years with a modern size-based formula

Compute sunrise, sunset, golden hour, and twilight times for any date and coordinates offline

Compare two tire sizes for diameter, width, circumference, and speedometer error.

Compute required visitors per variant from baseline conversion rate, MDE, significance, and power.

Calculate daily calorie, protein, carbohydrate, and fat targets from your body, activity, and goal.

Compute golden-ratio complements, split a length, and compare Fibonacci approximations of phi.

Count working days between two dates, excluding weekends and custom holidays.

Run one-sample, independent two-sample (Welch), and paired t-tests entirely in your browser, with p-values, degrees of freedom, Cohen's d effect size, and 95% confidence intervals.

Estimate how much paint you need for any room or exterior project. Enter wall dimensions, subtract doors and windows, set coats, coverage rate, and waste — get gallons, liters, cans to buy, and total cost.

Estimate roof surface area, shingle bundles or roof sheets, underlayment rolls, roofing squares, and cost from your building footprint and roof pitch. Gable and hip roofs, imperial and metric, 100% client-side.

Estimate how many tiles you need from surface and tile dimensions, with grout spacing, waste allowance, and box estimates.

Simplify ratios to lowest terms, solve missing proportion terms, compare two ratios, and scale quantities with equivalent-ratio tables.

Find your Western zodiac sign and Chinese zodiac animal element from your birthdate, with all 12 sign date ranges shown.

Calculate the best bedtime or wake-up time using 90-minute sleep cycles. Adjustable cycle length, fall-asleep buffer, and recommended 5-6 cycle highlights.

Tap along to any song to find its tempo in BPM with average, interval range, and tap count — works fully offline.

Compare product prices per kg, liter, ounce, or piece to find the true best value at the supermarket.

Estimate your ovulation day and 6-day fertile window from your last period start and average cycle length. See peak fertility days, next expected period, best pregnancy test day, and projections for the next 3 cycles.

Solve any 9x9 Sudoku instantly or generate printable puzzles by difficulty

Find the moon phase for any date: illumination percent, lunar age, distance, and the exact times of the next new moon, first quarter, full moon, and last quarter — all computed offline.

Run chi-square goodness-of-fit and independence tests on categorical counts — χ², p-value, df, critical value, residuals, and Cramér's V, all in your browser.

Estimate EV charging costs from battery size, charge level, and electricity tariff, with cost per km and a petrol car comparison.

Size a rooftop solar PV system from monthly usage, peak sun hours, and panel wattage.

Compute riser height, tread depth, number of steps, total run, and stair angle from floor-to-floor height, with 2R+T comfort checks. Works in cm or inches, fully offline.

Convert SLA uptime percentages like 99.9% into allowed downtime per day, week, month, and year — or measure achieved availability from real downtime, with a 99%–99.999% tier reference table.

Compute dew point, relative humidity, absolute humidity, and vapor pressure from temperature and humidity using the Magnus-Tetens formula, or reverse from dew point to relative humidity, with a comfort scale.