Construction Calculators
141 tools across fourteen groups — concrete, rebar, masonry, finishes, earthwork, temporary works, general, conversions, areas, material weights, construction planning, costing, building services and code lookups. Each page shows its formula, the standard behind it and the questions people actually ask.
No calculators match. Try concrete, rebar, volume or brick.
Concrete 15
▦Concrete Volume CalculatorEnter length, width and thickness to get the concrete volume you need and how many truck loads that is.▥Formwork Area CalculatorPick a member type, enter section and length, and get the formwork contact area plus sheet and batten estimates.◎Concrete Mix Design CalculatorWork out cement, sand, gravel and water per cubic metre from the target grade and water-cement ratio.◍Cement Quantity CalculatorGet total cement, bag count and the cement/fly-ash split for a given volume and grade.▤Concrete Pour Sequencing CalculatorDivide a slab into strips and get the volume, truck count and duration for each pour.⊞Concrete Strength ConverterConvert between grade, MPa, psi and kgf/cm², with cube-to-cylinder correction.◐Concrete Curing and Maturity CalculatorTurn curing temperature into maturity and equivalent age, and check the code minimum.▥Concrete Saw Cut Spacing CalculatorJoint spacing, saw depth and the sawing window from slab thickness.≡Concrete Yield CalculatorConvert batch weights and density into actual yield and per-m³ contents.▽Concrete Pumping CalculatorReal output, pour duration and the truck fleet needed to keep the pump fed.◧Site Mix Adjustment CalculatorEnter the lab mix and moisture content to get real batch weights.◎Mass Concrete Temperature CalculatorPlacement temperature, adiabatic rise and peak temperature in one step.◈Admixture Dose CalculatorPercentage dose to kg per m³ and per batch, with the new w/b ratio.▥Grout Quantity CalculatorVolume, weight, bags and water in one pass.◭Shotcrete Quantity CalculatorBack-calculate batched volume and material use from rebound.
Rebar 17
≡Rebar Weight CalculatorPick a bar diameter, enter length and quantity to get weight per metre, per bar and total tonnage.≡Rebar Anchorage Length CalculatorBasic and seismic anchorage length from bar grade, diameter and concrete class.⇄Rebar Lap Length CalculatorLap length ll / llE by splice percentage, plus the permitted number of splices.▭Rebar Cut Length CalculatorCut length and bar weight with standard hook allowances.⋮Rebar Spacing and Bar Count CalculatorBars and actual spacing from run length and design spacing, with total weight.▣Stirrup Length and Count CalculatorStirrup length, count and weight with the 11.9d seismic hook allowance.▦Rebar Mesh Weight CalculatorWeight per square metre and total mesh weight from dimensions and spacings.⇉Rebar Splice Percentage CalculatorSplice percentage at a section, code check and maximum permitted splices.⌐Rebar Bend Deduction CalculatorHow much to deduct per bend when converting out-to-out to centreline length.⌇Rebar Hook Length CalculatorAdded length for three hook types, with the seismic tail check.⌗Anchorage Length Modification Calculatorlab times correction factors, applying the no-combination rule for 0.8 and 0.7.▦Reinforcement Ratio Calculatorρ = As/(b·h0), and the reverse calculation for required steel.▩Slab Rebar Quantity CalculatorBar counts, total length and weight for two-way slabs.▬Raft Foundation Rebar CalculatorTop and bottom layers plus stools in one calculation.⊶Mechanical Splice CalculatorSplices and couplers from stock length, with the percentage check.⊓Rebar Stock Cutting CalculatorSegments, offcut, purchase quantity and utilisation.⊞Rebar Quantity EstimatorFloor area × steel rate for early-stage estimation.
Masonry 9
▤Brick Wall CalculatorPick a wall thickness, enter length and height, deduct openings, and get brick count plus mortar volume.◍Mortar CalculatorChoose brickwork or plastering, enter area and thickness, and get mortar volume plus cement and sand quantities.▤AAC Block Quantity CalculatorBlock count, volume and adhesive from wall size and block format.▥Hollow Brick Quantity CalculatorBrick count, mortar volume and bricks per m³ from wall thickness and format.◍Masonry Mortar Mix CalculatorCement, sand and water for M5-M15 mortar by volume, with a batch sheet.⇥Masonry Tie Bar CalculatorTie bar count, weight, holes and resin from wall and spacing.▮Tie Column Quantity CalculatorTie column count, concrete, formwork and rebar from wall and section.⊣Masonry Tie Bar Length CalculatorTotal length, count and weight, with seismic embedment rules.⌒Lintel Load and Moment CalculatorWall load above the opening, moment and steel estimate.
Finishes 19
◐Paint Coverage CalculatorEnter room size, ceiling height, openings and number of coats to get total area, litres needed and how many cans to buy.▩Tile CalculatorEnter the area to cover, pick a tile size and waste factor to get tiles and boxes required.▩Flooring Quantity CalculatorPlanks and packs from room size and board format, with waste by laying pattern.▥Wallpaper Roll CalculatorDrops and rolls from perimeter, height and pattern repeat.⊞Ceiling Grid CalculatorMain and cross runner lengths, hangers and fittings from ceiling size.▭Plasterboard Quantity CalculatorSheets, screws and joint tape from area, sheet size and layers.▬Skirting Board CalculatorMetres and lengths from perimeter and doorways, with waste.◫Door and Window Casing CalculatorCasing metres, pieces and board area from opening size and quantity.⌇Sealant Quantity CalculatorLength × width × depth straight to cartridges.▤Tile Adhesive CalculatorNotch depth drives the quantity: about 1.6 kg/m² per mm.▧Putty Quantity CalculatorArea × coats × consumption to bags.⊞Tile Grout CalculatorJoint length from tile size, then cartridges.▯Stone Dry-Hanging CalculatorMullions, rails, brackets and panels in one pass.⊪Steel Stud Partition CalculatorStuds, boards, screws and infill in one go.▢Curtain Wall Panel CalculatorPanels, mullions, transoms, glass area and aluminium.⊓Railing Post and Gap CalculatorPost count plus clear-gap compliance check.⊔Suspended Ceiling Developed Area CalculatorPlan area plus step reveals, priced by developed area.▬Floor Screed Material CalculatorVolume to cement, sand and water by mix ratio.▥Wall Tile Count CalculatorNet area after openings to pieces and boxes.
Earthwork 3
▽Earthwork CalculatorEnter pit dimensions and slope ratio to get cut volume, backfill and spoil to remove.▽Backfill Volume CalculatorBackfill volume, soil required, surplus to remove and truck loads.▬Compaction Degree CalculatorDry density and compaction degree from field density, with a pass/fail check.
Temporary works 3
⊞Scaffolding CalculatorEnter the wall perimeter and scaffold height to get the area plus tube, coupler and board quantities.▥Formwork Turnover CalculatorInitial formwork area and replacement allowance from total area and cycles.⊞Full Scaffold Material CalculatorStandards, tube length and weight, couplers and board area.
General 1
Unit conversion 10
↔Length Unit ConverterMetres, millimetres, feet and inches — every unit shown at once.▭Area Unit ConverterSquare metres, hectares, mu and square feet — all units at once.◫Volume Unit ConverterCubic metres, litres, gallons and cubic feet — all units at once.⚖Weight Unit ConverterTonnes, kilograms, jin and pounds — every unit at once.◉Pressure Unit ConverterMPa, kPa, bar, psi and kgf/cm² — every unit at once.⇉Force Unit ConverterkN, N, tonne-force, kgf and lbf for loads and lifting.🌡Temperature ConverterCelsius, Fahrenheit and Kelvin, with site temperature references.∠Angle ConverterDegrees, minutes, radians and slope percent, all at once.⇢Flow Rate Converterm³/h, L/s, L/min and GPM — every unit at once.⚡Power and Heat ConverterkW, horsepower, kcal/h, BTU/h and tons of refrigeration.
Area and volume 8
◱Room Area CalculatorFloor, ceiling, walls, skirting and volume, all at once.▯Wall Area and Paint CalculatorNet wall area with openings deducted, plus paint and filler.⌂Roof Area CalculatorTrue sloped roof area, rafter length and ridge rise from pitch.◯Circle and Sector CalculatorCircle area and circumference plus sector, arc, chord and segment.△Triangle Area CalculatorArea from three sides, with angles, inradius and circumradius.◣Battered Pit Volume CalculatorTop dimensions and frustum volume from base size, depth and batter.⬭Cylinder Volume CalculatorVolume, capacity, surface areas and weight for any cylinder.⌐Stair CalculatorRiser count and height, run, slope length and slab area, with comfort check.
Material weights 12
◎Steel Pipe Weight CalculatorMass per metre, per length and in total from OD and wall thickness.▬Steel Plate Weight CalculatorMass per square metre, per plate and in total from size and thickness.▮Round, Square and Flat Bar Weight CalculatorMass per metre and total for round, square and flat bar.∟Equal Angle Weight CalculatorMass per metre and total for equal angle steel.◍Stainless Steel Tube Weight CalculatorMass per metre and total for stainless tube.▤Aluminium Plate Weight CalculatorMass per square metre, per plate and in total for aluminium.▢Glass Weight CalculatorMass per square metre, per pane and in total for glass.▩Stone Weight CalculatorMass per square metre and total for stone slabs by density.▥Timber Volume and Weight CalculatorVolume, board area and weight for timber by species density.▦Sand and Gravel Tonnage ConverterCubic metres to tonnes by bulk density, with truck loads.▨Soil Haulage CalculatorNatural to loose volume, tonnes and truck loads without overloading.▣Cement Bag CalculatorTotal cement, exact bags and whole bags to order.
Construction 10
▤Plaster and Render CalculatorMortar, cement and sand by layer for internal plastering.◐Mortar Mix Design CalculatorTrial strength, cement, water and sand, and the mix by mass.⚒Labour Days and Crew CalculatorMan-days, crew size and labour cost from output rates.⇉Line-of-Balance Duration CalculatorRhythmic flow duration with overlap and break adjustments.▥Material Storage Area CalculatorNet footprint, total area and a suggested bay size.◍Dewatering CalculatorPit inflow by the equivalent-well method, then well count.⊙Bored Pile Concrete and Rebar CalculatorConcrete volume, overbreak factor and reinforcement for bored piles.⬡High Strength Bolt Torque CalculatorPreload by size and class, with snug and final torque.◷Formwork Striking Time EstimatorStriking times for side and soffit forms by member and temperature.▧Waterproofing Area and Membrane CalculatorTotal area with upstands, membrane rolls and primer.
Costing 10
¥Cost per Square Metre EstimatorCost per m² and in total by structure, region and finish.◫Concrete Cost CalculatorMaterial, pumping and the all-in rate per cubic metre.≡Rebar Cost CalculatorMaterial, fabrication, fixing and the all-in cost per tonne.☰Labour Cost Build-up CalculatorDay rate build-up with overheads, levies and tax.▤Formwork Cost CalculatorAmortisation, labour, support and the all-in rate per m².⊞Scaffolding Cost CalculatorRent by duration plus erection labour, giving total cost.%Construction VAT CalculatorOutput tax, input credit, VAT payable and surcharges.∑Unit Rate Build-up CalculatorBuild up an all-in unit rate from labour, material and plant.⌛Progress Payment CalculatorAdvance recovery, retention and the amount due this period.✎Variation Order Cost CalculatorFull cost of a variation and the change against the original rate.
M&E 10
⌇Cable Size CalculatorDesign current from load, then the conductor size to carry it.↯Voltage Drop CalculatorPercentage voltage drop with a 5% compliance check.◫Circuit Load and Breaker CalculatorDesign current, breaker loading and suggested ratings.≋Cable Ampacity Derating CalculatorTemperature, installation and grouping derating in one step.☀Lighting Level and Fixture CalculatorLumen method fixture count, achieved lux and power density.◌Water Demand CalculatorPeak day and peak hour demand, with pipe and tank sizing.⊘Water Pipe Sizing CalculatorBore from flow and velocity, with actual velocity and friction loss.⟍Drainage Pipe Slope CalculatorStandard slope by diameter, fall over the run and velocity check.⇡Pump Head CalculatorStatic lift plus losses, giving total head and shaft power.♨Heating Load CalculatorLoad, radiator sections, fuel use and running cost.
Code Lookup 8
▣Concrete Cover Thickness LookupMinimum cover from exposure class and member type, with every code correction applied.◈Seismic Detailing Class LookupIntensity, system and height in; detailing class and height check out.≣Column Confinement Zone CalculatorConfinement length, hoop spacing and bar size for each detailing class.▤Floor Live Load LookupPick an occupancy and read the characteristic live load in kN/m².◫Fire Compartment Area LookupCategory, fire rating and sprinklers in; compartment limit out.⇥Travel Distance to Exit LookupTravel distance by occupancy, with all three code corrections.⇔Egress Width CalculatorOccupants times the per-100-persons index gives total width and exit count.◉Concrete Strength Acceptance CalculatorSwitches between statistical and non-statistical criteria automatically.
Temporary Works 6
▤Formwork Lateral Pressure CalculatorSmaller of the two GB 50666 formulas, plus effective head height.☂Roof Drainage CalculatorCatchment area to flow to downpipe count.◺Roof Slope Layer CalculatorAverage thickness and volume from span and slope.▨Insulation Thickness CalculatorInsulation thickness from a target U-value.⇹Movement Joint Width CalculatorJoint width from thermal movement plus allowances.⊞Scaffold Tie CalculatorTie count from perimeter and height, with spacing limits checked.
About these calculators
Everything runs in your browser. No data is uploaded and the tools work offline. Formulas follow national standards and common trade practice, and each page states its assumptions. Where a local code or estimating rule differs, the local rule governs.
Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.