Tools
Calculators for everything that is not money
FigureBetter started with finance, and the money calculators are still next door. These are the rest: the standard deviation of a data set, how many bags of concrete a slab takes, what a 1280-pixel width does to a 16∶9 frame, the score you need on a final. Every one is free, needs no account, keeps your inputs on your own device, and shows the formula it used rather than asking you to trust the number.
Math & Statistics
Fractions, averages, spread, probability, geometry, and the algebra behind them.
FractionAdd, subtract, multiply, and divide fractions in lowest terms.Decimal to FractionExact fraction for any decimal, including repeating ones.Mean, Median, Mode & RangeEvery centre and spread statistic for a list of numbers.Standard DeviationSample and population deviation, variance, and standard error.Z-ScoreHow many deviations from the mean, and the probability that implies.Confidence IntervalThe margin of error around a sample mean at any confidence level.Sample SizeHow many responses a survey needs for a given margin of error.ProbabilityUnion, intersection, complement, and conditional probability.Permutations & CombinationsnPr and nCr, with exact answers well past the float limit.Factorialn! exactly, however many digits that turns out to be.Quadratic FormulaRoots, discriminant, and vertex for any quadratic equation.Slope & Line EquationSlope, intercept, distance, and midpoint from two points.ExponentPowers with negative and fractional exponents handled properly.Square RootSquare, cube, and nth roots, plus simplified radical form.LogarithmSolve for any of the three parts of log base b of x.RatioSimplify a ratio, solve A∶B = C∶D, or scale one to a total.GCF & LCMGreatest common factor and least common multiple for any list.Prime FactorizationBreak a number into its prime factors, in exponent form.Significant FiguresCount the significant figures in a number, or round to a count.Scientific NotationConvert to and from scientific notation without losing precision.Percent ErrorHow far an observed value sits from the expected one.Area of a ShapeArea for seven shapes, from rectangles to sectors.Volume of a SolidVolume for cubes, cylinders, spheres, cones, and pyramids.Triangle SolverSolve any triangle from SSS, SAS, ASA, or two right-angle sides.CircleRadius, diameter, circumference, and area from any one of them.
Unit Conversion
Length, weight, temperature, volume, and eleven more unit families.
LengthMetres, feet, inches, miles, and nine more length units.Weight & MassKilograms, pounds, stones, ounces, and tonnes.TemperatureCelsius, Fahrenheit, and Kelvin — an offset, not just a factor.VolumeLitres, gallons, cups, and the US-versus-imperial gap.AreaSquare metres, square feet, acres, and hectares.SpeedMiles per hour, kilometres per hour, knots, and metres per second.Time UnitsSeconds through years, with exact rather than rounded months.Data StorageBytes to terabytes, decimal (GB) and binary (GiB) both.PressurePascals, bar, psi, atmospheres, and millimetres of mercury.EnergyJoules, calories, kilowatt-hours, and British thermal units.AngleDegrees, radians, gradians, and degrees-minutes-seconds.Fuel EconomyUS mpg, imperial mpg, and litres per 100 km — a reciprocal, not a factor.Number BaseBinary, octal, decimal, hex, and every base from 2 to 36.Roman NumeralsArabic to Roman and back, with the subtractive rules applied.Cooking MeasurementsCups, grams, and millilitres — by ingredient, because density differs.
Health & Fitness
Body composition, energy needs, training paces, and pregnancy dates.
BMIBody mass index in metric or imperial, with the WHO bands.BMRResting energy burn by Mifflin-St Jeor, Harris-Benedict, or Katch-McArdle.TDEETotal daily energy expenditure — maintenance calories, three ways.Calorie TargetCalories for a goal weight, and the date you would reach it.MacrosProtein, carbs, and fat in grams from a calorie target.Body FatUS Navy circumference method, with the BMI method alongside.Ideal WeightFour classic formulas plus the healthy-BMI range they disagree with.Lean Body MassEverything that is not fat, by Boer, James, or Hume.Protein IntakeGrams of protein a day for maintenance, loss, or muscle gain.Pregnancy Due DateDue date from last period, conception, or IVF transfer.Running PacePace, time, or distance — fill any two and get the third.One-Rep MaxEstimated 1RM by Epley, Brzycki, and Lombardi, plus a percentage table.Calories BurnedEnergy cost of an activity from its MET value and your weight.Heart Rate ZonesFive training zones by percentage of max or heart-rate reserve.Steps to MilesDistance from a step count, using stride length from your height.
Home & Construction
How much concrete, paint, tile, or lumber a job actually needs.
Square FootageTotal floor area across several rooms, and the cost per square foot.ConcreteCubic yards and bag counts for slabs, footings, columns, and tubes.PaintGallons needed once doors, windows, and second coats are counted.MulchCubic yards and bags of mulch for a bed at a given depth.Gravel & AggregateVolume and tonnage for gravel, sand, or crushed stone.TileTile count and boxes, with a waste allowance for cuts.FlooringBoxes of laminate, vinyl, or hardwood for a room.RoofingSquares and bundles of shingles, adjusted for roof pitch.DrywallSheets, joint compound, tape, and screws for a room.FencePosts, rails, and pickets from a run length and post spacing.StairsRiser count and height, tread depth, and total stringer run.BTU & Room SizeHeating and cooling capacity a room needs, by area and climate.
Time & Date
Ages, durations, working days, timesheets, and calendar arithmetic.
AgeExact age in years, months, and days on any given date.Date DurationDays, weeks, and months between two dates.Add or Subtract TimeThe date a number of days, weeks, or months from another.Business DaysWorking days between dates, minus US federal holidays.Time CardWeekly hours from clock-in and clock-out times, breaks deducted.Time DurationAdd and subtract hours, minutes, and seconds.Days UntilCountdown from today to any future date.Day of the WeekWhich weekday any date in history falls on.Week NumberISO 8601 week number for a date, and the dates in a week.Military Time24-hour and 12-hour clock, converted both directions.Unix TimestampEpoch seconds to a UTC date, and back.Sleep & BedtimeBedtimes and wake times that land between 90-minute cycles.
Grades & School
Current grade, the score you need on the final, and GPA.
GradeCurrent grade from weighted assignment categories.Final GradeThe score you need on the final to hit a target grade.GPATerm GPA from credits and letter grades, weighted or not.Cumulative GPANew cumulative GPA after adding a term to your record.Test GradePercentage and letter grade from questions right and wrong.Easy GraderThe full score-to-percentage table for a test of any length.Weighted AverageAverage where each value carries its own weight.Grade CurveFlat, square-root, and linear-scale curves applied to a class.
Everyday Utility
Word counts, fuel costs, aspect ratios, and other small answers.
Word CounterWords, characters, sentences, and paragraphs in a passage.Random NumberNumbers in a range, unique or repeating, from a seed you can share.Aspect RatioResize while keeping proportion, and name the ratio.Fuel CostWhat a trip costs in fuel, and the cost per person.Gas MileageReal-world mpg or L/100 km from a tank and an odometer.Electricity CostWhat an appliance costs to run per day, month, and year.Dog AgeDog years by size class, and by the 2019 epigenetic curve.Cat AgeCat years using the AAFP/AAHA feline life stages.Tire SizeCompare two tire sizes for diameter, and speedometer error.Recipe ScalerScale ingredient quantities to a different number of servings.Reading TimeHow long a piece takes to read or to say out loud.Wind ChillWhat the cold actually feels like, by the NWS 2001 formula.Dimensional WeightBillable shipping weight when a box is big but light.
Looking for the money side?
A hundred personal-finance calculators — mortgages, loans, debt payoff, retirement, taxes and take-home pay — live at the main catalog. The everyday money tools people reach for most, percentage, tip and discount, are over there too.