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.

Compute shipping volumetric weight from length, width, and height with IATA and courier divisors, compare carriers side by side, and see which weight you will be billed for.

Add and subtract SMPTE timecodes (HH:MM:SS:FF) at 24, 25, 30, or 60 fps and convert total frames to timecode - frame-accurate math for video editing, in your browser.

Compute the great-circle distance (Haversine) between two lat/lng points in kilometers, miles, and nautical miles, plus the initial bearing with a compass direction.

Convert your cat's age into human-equivalent years with the accelerated first-two-year growth model, plus the matching life stage from kitten to geriatric.

Estimate remaining life expectancy from age, sex, smoking, weight range, and exercise using a bundled actuarial table - instantly, privately, and fully offline.

Fit a least-squares regression line to pasted X/Y data - get slope, intercept, R², and the correlation coefficient with a scatter plot, entirely in your browser.

Predict a child's adult height from parents' heights using the mid-parental height formula with a percentile range output - instant, private, in your browser.

Suggest the fastest dart checkout routes from any remaining score 2-170 with T20 finishes, Bull options, and alternate routes - pure client-side math.

Run one-way ANOVA on pasted group datasets with F statistic, p-value, eta-squared effect size, and Bonferroni-adjusted pairwise comparisons - all client-side.

Calculate how many five-star reviews you need to reach a target average rating from your current review count and score - exact math, instant results, fully client-side.

Compute which plates to load per side for any target weight - kg or lb denominations, your own plate inventory, bar weight, and the exact remainder when the target is not reachable. Client-side.

Count SMS segments and estimate cost with GSM-7 vs UCS-2 rules - auto encoding detection, 160/153 and 70/67 segment math, extension-character double counts, and per-character warnings. Client-side.

Compute depth of field, hyperfocal distance and near/far focus limits from focal length, aperture, subject distance and sensor format.

Find the optimal TV or monitor size for your viewing distance — or the distance for a given size — using THX and SMPTE viewing-angle guidelines plus 1080p/4K/8K pixel-visibility limits.

Compute floor area of rectangles, circles and triangles with unit conversion and cost-per-area totals for real estate and DIY planning.

Compute 90/95/98/99% or custom confidence intervals for means and proportions, with margin of error, critical values and small-sample warnings.

Estimate drywall sheets, screws, joint compound, and joint tape from your room dimensions, ceiling and wall options, and door and window openings. Choose a sheet size, set the waste allowance, and adjust every consumption rate. Imperial and metric, 100% client-side.

Price a 3D print from filament, electricity, machine wear, failure rate, labor, and target margin with a full breakdown.

Type notes with inline math that auto-computes line by line - variables, units, sums, and functions - with a running results column.

Compute displacement hull speed, sail area-to-displacement and capsize screening ratios, and propeller slip from boat dimensions.

Explore aperture, shutter, and ISO trade-offs with EV math, an equivalent-exposure table, and a live brightness preview on canvas.

Compute your daily calorie target from TDEE and goal loss rate, project your goal date, and warn on unsafe deficits.

Recommend aquarium glass thickness and safety factor from tank dimensions, with water volume and glass weight.

Compute ideal wall-mount center height and tilt from eye level, viewing distance, and TV size using THX/SMPTE guidelines.

Compute how many items fit per carton and how many cartons fit per pallet/container with orientation rotation and fill-ratio stats.

Work out how many pavers you need with pattern waste, base sand and gravel volumes, edge restraints, and full cost totals

Compute board feet and total lumber cost for multiple plank sizes with species price presets and a waste allowance

Draw up to 8 people or objects to scale on a shared height chart with silhouette bars and PNG export

Estimate cardio fitness (VO2 max) from a Cooper 12-minute run, a race result, or resting heart rate, with fitness classes and percentile

Compute water volume in rectangular, circular, oval, and kidney pools in gallons and liters, with turnover time and chlorine dosing

Compute a World Handicap System Handicap Index from your recent scorecards: Score Differentials from Course Rating and Slope Rating, the lowest-N selection table of Rule 5.2a, an Adjusted Gross Score capped at net double bogey per hole, and the soft cap, hard cap and 54.0 ceiling.

Compute gear inches, development meters, gain ratios and speed at cadence from chainring and sprocket teeth, wheel size and crank length, with a gear-step comparison table across a full cassette. Runs entirely in your browser.

Predict your 5K-to-marathon finish times from a recent race result with the Riegel exponent model, equivalent paces per km and mile, negative-split and fade scenarios, and training-pace zones. Runs entirely in your browser.

Estimate deck boards, joists and screws from deck dimensions with board width, gap spacing, board length, joist spacing, waste allowance and cost totals for boards and joists. Pure client-side math.

Compute fence posts, rails and pickets from perimeter length and gate counts with post spacing, picket width and gap, concrete bag estimates per post hole and full cost totals. Pure client-side math.

Estimate countertop slab count, edge-finishing length and installed cost from kitchen dimensions, with sink and cooktop cutout deductions, waste allowance and price inputs for slabs, edges and installation. Pure client-side math.

Compute mulch bags or bulk cubic meters needed from garden-bed area and depth, with bag-size presets, a bag versus bulk cost comparison and a coverage chart at common depths. Pure client-side math.

Do exact arithmetic on huge integers beyond Number.MAX_SAFE_INTEGER — factorials, powers, sums, products and floor division with remainder — using BigInt math with thousands separators and digit-count statistics. Pure client-side.

Map any date to its fiscal quarter for a calendar or custom fiscal-year start month, showing quarter start and end dates, days remaining, the fiscal-year label and a full FY-to-Gregorian crosswalk table. Pure client-side math.

Compute ideal sitting and standing desk heights plus elbow and eye placement from your body height using classic ergonomic ratios, with monitor placement guidance. Pure client-side math.

Dial in pour-over, espresso, French press, cold brew, moka pot and drip recipes from dose, water and ratio with method presets, bloom water split, a strength guide and multi-cup scaling. Pure client-side math.

Estimate blood alcohol content over time via the Widmark formula from standard drinks, body weight, sex and elapsed hours, with time-to-zero and legal-limit thresholds and a prominent estimates-only disclaimer. Pure client-side math.

Estimate vinyl or lap siding squares, trim linear meters and cost totals from wall perimeter, height, gable area and opening deductions, with waste allowance and quarter-square rounding. Pure client-side math.

Calculate your attendance percentage from classes attended versus total classes held, see how many more classes you need to reach a 75% requirement or how many you can still miss, and keep a dated per-subject and month-wise log saved offline in your browser.

Calculate the required run rate for a cricket chase from target, current score and balls remaining, compare it with the current run rate, and see an over-by-over plan, projected score, proportional par hints and a plain-English verdict.

Compute gravel, crushed stone or sand tonnage and cost from driveway or path area and depth, with material density presets, a compaction allowance and a depth coverage chart. Pure client-side math.

Set grade boundaries by points, convert marks to letter grades and GPA, and compute the score needed on the final exam to reach a target grade. Pure client-side math.