Concrete calculators

19 concrete calculators: volume, formwork area, mix ratio, cement quantity, pour sections, curing time, joint spacing, mass concrete temperature, admixtures and blinding.

19 tools, most used first

▦Concrete Volume CalculatorEnter length, width and thickness to get the concrete volume you need and how many truck loads that is.◎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.▥Formwork Area CalculatorPick a member type, enter section and length, and get the formwork contact area plus sheet and batten estimates.◐Concrete Curing and Maturity CalculatorTurn curing temperature into maturity and equivalent age, and check the code minimum.▭Post-Cast Strip CalculatorEnter strip length, width, slab thickness and waterstop size to get concrete volume plus waterstop length and weight.◎Mass Concrete Temperature CalculatorPlacement temperature, adiabatic rise and peak temperature in one step.▤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 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.◈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.▤Strip Footing CalculatorConcrete, blinding, formwork and base area for strip footings.▦Pile Cap CalculatorConcrete, two-way bottom steel, formwork and blinding per cap.▭Blinding and Cushion CalculatorPlan size, concrete volume and side formwork for blinding.

What this group solves

Concrete is the material where estimating errors cost the most: a cubic metre short means a cold joint or a second small pour, a cubic metre over is money in the skip, and once it starts to set there is no rework. These tools cover the whole chain — volume from the concrete volume calculator, formwork area, cement and aggregate from the mix ratio and cement quantity calculators, then curing and striking times to plan the sequence.

The two things most often missed on site are waste and temperature. Volume results already carry a waste allowance you can tune for pumping, direct discharge or barrows, and there is a separate tool for mass concrete that estimates peak core temperature and the core-to-surface differential from placement temperature, heat of hydration and ambient conditions. Blinding, strip footings, pile caps and construction joints each have their own tool rather than being forced through a generic volume formula.

FAQ

How do I calculate concrete volume?

Length × width × depth for a slab or rectangular element, π × radius² × depth for a column or pile. Break irregular shapes into simple blocks and add them. Then add waste: 1-2% for pumped concrete, 2-3% for direct discharge, 3-5% for barrow work, at the top of the range for blinding and slabs where level control is loose.

How much cement, sand and aggregate per cubic metre?

It depends on grade and mix design. A typical C25 mix uses about 370-400 kg cement, 580-620 kg medium sand, 1250-1280 kg crushed stone and 175-185 kg water per cubic metre. Use the mix ratio calculator for your grade and cement type, then the cement quantity calculator to convert to 50 kg bags.

When can formwork be struck?

Side forms after about 24 hours once strength reaches 1.2 MPa. Soffits depend on span: 50% of design strength up to 2 m, 75% for 2-8 m, 100% beyond 8 m — roughly 3, 7 and 28 days at 20°C. In cold weather go by companion cubes, not by the calendar.

Related data tables

Material density tableCheck this before converting volume to weight — bulk and solid density differ by a factor of two, and picking the wrong one ruins the tonnage.

Other groups

Rebar Masonry Finishes Earthwork Temporary Works Construction Costing M&E Material weights Area and volume Unit conversion Code Lookup

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.