Everyday calculators

Unit conversion, home and trade quantities, food and the practical calculations daily life runs on.

Conversion

Unit converters that show the full ladder of equivalents at once, not just the one pair you asked for.

Length & distanceMetric and imperial length, from millimetres to nautical miles.Weight & massGrams, kilograms, pounds, ounces, stone and tonnes.Volume & capacityLitres, millilitres, gallons, pints, cups and cubic units.AreaSquare metres, hectares, acres and square feet.SpeedKilometres per hour, miles per hour, metres per second, knots.TimeSeconds through to centuries.Digital storageBytes, kilobytes, mebibytes and the binary versus decimal split.PressurePascals, bar, psi, atmospheres and millimetres of mercury.EnergyJoules, calories, kilowatt-hours and BTU.PowerWatts, kilowatts, horsepower and BTU per hour.AngleDegrees, radians, gradians and turns.Cooking measuresCups, spoons, millilitres and fluid ounces for the kitchen.TemperatureCelsius, Fahrenheit, Kelvin and Rankine.Fuel economyLitres per 100 km, miles per gallon and km per litre.Height & weight (imperial ↔ metric)Feet-and-inches and stone-and-pounds, both ways.TorqueNewton-metres, foot-pounds, inch-pounds and kilogram-force metres.Paper quantitySheets, quires and reams, the units the printing and stationery trade uses.Concentration (ppm, ppb, %)Parts per million, parts per billion and percentage, as the same ratio expressed differently.12-hour ↔ 24-hour (military) timeClock time converted to 24-hour military format, and back.Astronomical distance (AU, light-year, parsec)Distances across the solar system and beyond: astronomical units, light-years and parsecs.Degrees, minutes, seconds ↔ decimal degreesConverts a geographic coordinate between decimal degrees and degrees-minutes-seconds format.

Home & build

Quantities and sizing for renovation, landscaping and trade work: paint, tiles, concrete, roofing and more.

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Paint requiredLitres of paint for walls, allowing for doors and windows.Flooring & tilesBoxes of tiles or boards needed, including wastage.Concrete volumeCubic metres for a slab, footing or set of posts.Mulch, soil & gravelBulk material for a garden bed at a given depth.Roof pitch & rafter lengthAngle, slope factor and true roof area.Fencing & decking materialsPosts, rails and boards for a run of fence or deck.Air conditioner sizingCooling capacity for a room, adjusted for sun and occupancy.Tank & pool volumeCapacity of a rectangular or round tank in litres.Drywall sheets neededPlasterboard sheets for a room, allowing for openings and waste.Bricks or blocks neededMasonry units for a wall, from unit size and mortar joint thickness.Stair rise & runStep count, riser height and comfort check for a straight staircase.Pavers & bedding sandNumber of pavers and bedding sand volume for a patio or path.Roof shingle bundlesBundles of shingles needed, accounting for slope and waste.Board feet of lumberBoard feet and cost for a batch of dimensional lumber.Baluster / spindle spacingEven spindle count and gap for a stair or deck railing.Wallpaper rolls neededRolls required for a room, accounting for pattern repeat.Wall stud countStuds needed for a wall on a chosen centre spacing, plus openings.Ladder angle & base distanceSafe base distance and length for a leaning ladder, using the 4-to-1 rule.Insulation thickness & coverageThickness needed to hit a target R-value, and rolls required for an area.Air changes per hour (ACH)Ventilation rate for a room, from fan airflow and room volume.Door / window header sizeMinimum header depth for a rough opening, using the standard light-framing rule of thumb.Fence post hole depthHow deep to set a fence or deck post below grade, and the total post length to buy.Post hole concreteConcrete needed to set posts in round holes, allowing for the post itself.Board and batten sidingBattens needed to cover a wall at a chosen spacing, plus base board coverage.French drain materialsGravel and pipe needed for a French drain trench.Rebar for a concrete slabBar count and total length for a two-way rebar grid in a slab or footing.Tile grout neededWeight of grout for a tiled area, from tile size and joint dimensions.Ramp slope & lengthSlope ratio, angle and ramp length for a given rise, checked against the ADA maximum.Retaining wall blocksNumber of retaining wall blocks for a wall from its length, height and block size.Deck footing countNumber of footings for a deck frame at a chosen maximum footing spacing.Well water volumeWater volume held in a well casing from its diameter and the water column depth.Roof truss countNumber of roof trusses for a building length at a chosen on-centre spacing.Board-on-board fenceBoards, posts and rails for a board-on-board fence, from the board overlap.Rolling offset (pipefitting)True offset, travel and run for a pipe that must dodge an obstacle both sideways and up.Concrete block core fillGrout volume to fill the hollow cores of concrete masonry blocks.Floor area ratio (FAR)Ratio of building floor area to lot size, and the max floor area a zoning FAR limit allows.Paver sand neededVolume and weight of bedding or joint sand needed to cover a paver area at a given depth.Arch radius from rise and spanRadius of the circular arc that gives a doorway or window arch its rise and span.Sheet metal bend allowanceFlat pattern length added by a bend, from thickness, radius, angle and the K-factor.Sheet metal punch forceForce needed to punch a hole through sheet metal, from the hole perimeter and material.Bolt circle spacingStraight-line spacing between adjacent bolt holes evenly spaced on a bolt circle.Air changes per hourHow many times an hour a ventilation system replaces a room's air.Bathroom mirror sizeRecommended mirror width and height from your vanity and ceiling.Furnace size (BTU)Heating capacity needed for a home, from floor area, climate band and insulation.Metal bar & sheet weightWeight of a metal plate, bar or round rod from its dimensions and material density.Lumber weightWeight of dimensional lumber or a stack of boards, from species density and count.

Everyday

Practical comparisons for shopping, travel, cooking and time: the small calculations that add up.

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Trip fuel costFuel and time for a journey, split between passengers.Unit price comparisonWhich pack is actually cheaper per unit.Recipe scalerRescales quantities and adjusts baking time.Aspect ratio & screen sizeResize while keeping proportions, or find screen dimensions.Pizza & round-item valueArea per dollar: the honest way to compare sizes.Reading & speaking timeHow long a word count takes to read aloud or silently.Password strengthEntropy in bits and how long a brute force would take.Coffee brew ratioGrounds and water for a chosen strength.Hours of work to buy somethingPrices a purchase in hours of your life.Battery charge timeHow long a device takes to charge from its current level to a target level.Typing speed (WPM)Gross and net words per minute, and accuracy, from a timed typing sample.Luggage linear inchesChecks a bag against an airline’s combined length + width + height limit.Cost of a meetingWhat a meeting actually costs in attendee salary time.True cost per mile to driveAll-in running cost of a vehicle, spread across the miles driven.Weight of a pile of cashHow much a dollar amount weighs in bills or coins.2-stroke fuel mix ratioOil to add to a volume of petrol for a chosen mix ratio.Generator sizingGenerator capacity needed to cover a set of appliances, including starting surge.LED bulb savingsElectricity and replacement-bulb savings from switching to LED lighting.Event tables & seatingTables needed for a guest count, for round or rectangular tables.Pomodoro session plannerHow many focused work intervals a task will take, breaks included.Money saved by quitting smokingWhat not buying cigarettes adds up to over time.Roll length remainingHow much material is left on a roll, from its diameter and material thickness.Cost of a showerWater and water-heating energy cost for one shower.EV home charging cost & timeCost and time to charge an electric vehicle from one charge level to another.Binge-watch time plannerTotal time to finish a TV series, and how many days that takes.Moon phase finderThe approximate Moon phase on any date, from the lunar synodic cycle.Weighted blanket sizeRecommended blanket weight from body weight, using the common 10% rule.Mobile data usageDaily and monthly data use from your everyday activities, and how long a data cap will last.Carpool cost sharingSplits a shared commute's fuel cost fairly among riders.Commute cost & time comparisonCompares driving to public transit for a regular commute, in cost and time.Toilet paper: how long a pack lastsHow many days a pack of toilet roll lasts a household, from usage per person.Firewood needed for the seasonHow many cords of firewood a heating season needs, from stove burn rate and heating days.Tire size & speedometer differenceOverall diameter, circumference and speedometer error between two tire sizes.Crosswind & headwind componentSplits a wind reading into the part blowing across your path and the part blowing along it.Packing boxes estimateHow many moving boxes a household will need, from room count plus kitchen and fragile items.Belt sizeBelt size to buy from a waist measurement, using the standard buckle allowance.Standing desk heightStanding desk surface height from your height, using the elbow-height ergonomic ratio.Screen viewing distanceRecommended seating distance from a screen size and target field of view.Sunscreen amountSunscreen to apply per full-body application, from the dermatology 2 mg/cm² rule.Hammock hang angleRidgeline length and hang-point drop for a comfortable hammock sag between two anchors.Engine compression ratioStatic compression ratio for an engine cylinder from bore, stroke and clearance volume.Cross-stitch fabric sizeFabric size to buy for a cross-stitch pattern, from stitch count, fabric count and margin.Bean bag fillingFiller needed for a bean bag chair from its filled dimensions, using the standard bead density.Clay shrinkageFired size of a clay piece after drying and firing shrinkage, from its wet (greenware) size.Sidereal timeLocal sidereal time for a date, UTC time and longitude, the star clock astronomers use.Balloon arch balloon countBalloons needed for a single-row or garland balloon arch from its size and balloon diameter.Cost per minuteBreaks a total cost down to a rate per minute, for calls, rentals, or metered time.Price per weightUnit price of an item by weight, so you can compare packages sold in different sizes or units.Tablecloth sizeTablecloth dimensions needed for a table, from its size and how far you want the drop.Curtain fabric neededFabric width and panel count for curtains, from window size and desired fullness.Pool salt neededHow much salt to add to a saltwater pool to reach a target concentration.Bath vs. shower water useCompares the water used filling a bath against taking a shower of a given length.Hat sizeHat size number from head circumference, plus the letter size.Glove sizeGlove size number and letter size from a hand circumference measurement.Paper sheet & ream weightWeight of a sheet or a stack of paper from its GSM and dimensions.Helium balloon liftHow many balloons of a given size are needed to lift a payload.Winch sizeRecommended winch pulling capacity from vehicle weight and a safety factor.Lumens to wattsPower draw needed for a target brightness, by bulb technology.Event tent sizeFloor area and footprint needed for a party or event tent, by seating style.Toothpaste tube lifeHow many days a toothpaste tube lasts a household, from tube size and brushing habits.

Food

Kitchen and brewing ratios: baker’s percentages, dilutions, yields and the maths behind a recipe that scales.

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Baker’s percentage & hydrationExpresses each dough ingredient as a percentage of the flour weight, as bakers do.Brine strengthSalt needed to make a brine of a given strength, by weight of the water.ABV from gravity readingsAlcohol by volume of a home-brewed beer or wine from hydrometer readings.Alcohol dilutionWater needed to cut a spirit down from one ABV to a weaker target ABV.Yeast type converterA quantity of yeast converted between active dry, instant and fresh (cake) forms.Self-rising flour from all-purposeBaking powder and salt to turn plain flour into self-rising flour.Rice to water ratioWater needed to cook a given amount of rice, and the approximate cooked yield, by rice type.Dry to cooked pasta weightHow much a portion of dry pasta weighs once boiled, given its typical expansion factor.Party drink plannerTotal drinks needed for a party, split across beer, wine and spirits.Cake servingsHow many servings a round or rectangular cake yields at a given slice size.Ice cream overrunHow much the volume of a churned ice cream mix has grown from the air whipped into it.Cups to grams (ingredient weight)Converts a volume measure of a common ingredient to weight, using typical ingredient density.Turkey roasting & thawing plannerOven time and refrigerator/cold-water thawing time for a turkey, from its weight.Cake pan size converterRescales a recipe's batter amount when swapping to a different pan shape or size.BBQ / party food plannerProtein, sides and drinks to buy for a barbecue or party, per guest.Ham per personHow much ham to buy for a group, by bone-in or boneless serving guidelines.Priming sugarSugar to add for bottle-carbonating a home-brewed beer to a target CO2 level.Cake pricingA sale price for a custom cake from ingredient cost, labour and a target profit margin.Fresh to dried herb conversionDried herb amount to substitute for a fresh herb quantity in a recipe, or the reverse.Garlic form converterEquivalent amount of minced, powdered or granulated garlic for a number of fresh cloves.Turkey thawing timeTime needed to safely thaw a turkey in the refrigerator or in cold water, by weight.Bacon curing ratiosDry-cure salt, pink curing salt and (for wet brining) water for a pork belly, by weight.Molecular SO2 in wineThe antimicrobially active molecular SO2 fraction, from free SO2 and wine pH.Drink chilling timeTime for a drink to cool to a target temperature, using Newtons law of cooling.Ham cooking timeOven roasting time for a ham, from its weight and whether it is fully cooked or fresh.Mashed potatoes per personHow much mash to make and how many raw potatoes to buy for a group.BBQ grill sizeGrilling surface area needed for a cookout, and an equivalent round grill diameter.Egg boiling timeBoiling time for an egg by size and doneness, scaled from a large-egg baseline.Tea steeping guideRecommended water temperature and steep time by tea type, and leaves needed for a batch.Oil to butter converterConverts a recipe quantity between cooking oil and butter using the standard baking ratio.Popcorn yieldPopped popcorn volume from a quantity of unpopped kernels, and servings it makes.

Pets

Sizing, feeding and age-conversion maths for the animals in your household, from crate size to daily calories.

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Dog age in human yearsA dog's age converted to a human-equivalent age using the epigenetic-clock formula.Cat age in human yearsA cat's age converted to an equivalent human age using the standard veterinary chart.Pet gestation & due dateExpected birth date range for a common pet or farm animal, from the breeding date.Dog & cat daily caloriesDaily energy needs from resting energy requirement and an activity factor.Dog daily water intakeRoughly how much water a dog needs per day, by activity level.Dog crate sizeMinimum crate dimensions so a dog can stand, turn around and lie stretched out.Turtle tank sizeMinimum water volume for a pet turtle based on shell length.Chicken coop & run sizeMinimum floor space for a flock, depending on how much outdoor access they get.Dog chocolate toxicity riskTheobromine dose from chocolate eaten, checked against published toxicity thresholds.Rabbit cage sizeMinimum enclosure dimensions based on a measured hop, body length and standing height.Dog daily food amountDaily feeding amount as a percentage of body weight, by life stage.Cost of owning a petFirst-year and ongoing costs from your own monthly and one-off figures.Guinea pig & hamster ageHuman-equivalent age for a guinea pig or hamster from published veterinary age charts.Fish tank stockingRoughly how many inches of fish a freshwater community tank can hold.Pet bird ageHuman-equivalent age for a pet bird, scaled by its species’ typical lifespan.Horse weight estimateEstimated adult horse body weight from a heart-girth and body-length tape measurement.Round pen panel countFence panels needed to build a round training pen from its diameter and panel length.Dog harness sizeRecommended harness size from chest girth, the measurement harnesses are actually fitted to.Dog heat cycle predictorEstimated stage dates and next heat window from the last cycle's start date.Dog onion toxicity riskOnion dose eaten checked against published toxicity thresholds for a dog's weight.Fish weight estimateEstimated live weight of a fish from its length and girth, without using a scale.