Concrete Calculator
Calculate how much concrete you need for slabs, driveways, foundations, patios, paths, garage floors, post holes and other building projects. Compare ready mix concrete with site mixed concrete and calculate your requirement in cubic metres.
Select the ready mix concrete type you require. If you are unsure, the calculator will show a suggested option based on the project you selected. The final concrete specification should always be checked against your project requirements.
Your Concrete Requirement
C20/25
Estimated Site Mix Materials
Site mix materials estimate: £0.00
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Concrete Calculator UK
The ACS Concrete Calculator is designed to help tradespeople, builders, contractors, landscapers and DIY customers calculate how much concrete is required for a building or landscaping project. Enter the dimensions of your slab, driveway, patio, path, foundation, garage floor or other concrete application and the calculator will work out the approximate volume in cubic metres.
You can use the calculator for both ready mix concrete and site mixed concrete. The ready mix calculator calculates the volume you need to order, while the site mix calculator provides estimated quantities of cement, sand, aggregate and water based on the selected nominal mix.
Ready Mix Concrete Calculator
Ready mix concrete is supplied to site in a pre-batched form and is normally ordered by cubic metre. It can be an efficient option when a project requires a significant quantity of concrete, particularly where speed, consistency and reduced on-site mixing are important.
Use the ACS ready mix concrete calculator to estimate how many cubic metres you need for a concrete slab, driveway, foundation, garage floor, patio, path or other project. The calculator also allows you to add a waste allowance to your calculated volume.
How Much Ready Mix Concrete Do I Need?
For a simple rectangular slab, multiply the length by the width and the concrete thickness. Make sure all three measurements use the same units. The result is the volume in cubic metres when the dimensions are entered in metres.
For example, a slab measuring 5 metres long by 3 metres wide and 100mm deep requires approximately 1.5 cubic metres before a waste allowance is added.
Concrete Calculator for Driveways
A driveway can require a substantial quantity of concrete, making accurate volume calculations particularly important. Select the driveway option above and enter the overall length, width and concrete thickness to calculate the approximate volume.
The required concrete specification for a driveway depends on factors such as anticipated loading, ground conditions, reinforcement, exposure and the construction design. The calculator's suggested concrete type is therefore a guide rather than a structural specification.
Concrete Slab Calculator
Concrete slabs are commonly used for patios, shed bases, garage floors, extensions, workshops and other applications. Select Concrete Slab above, enter the length, width and thickness, and the calculator will provide the estimated concrete volume.
Remember that the finished slab thickness should be determined by the requirements of the project. Ground preparation, reinforcement, sub-base construction and drainage can all affect the overall construction.
Concrete Foundation Calculator
The foundation options in the calculator allow you to estimate concrete volume for rectangular foundation sections, strip footings and pad foundations. These calculations are useful for material planning, but they do not determine the correct foundation design.
Foundation dimensions and concrete specifications should be based on the building design, ground conditions, loading and applicable requirements. Where foundations are structural, obtain suitable professional advice before ordering concrete.
Post Hole Concrete Calculator
The post hole calculator uses the number of holes, hole diameter and hole depth to calculate the approximate volume of concrete required. This can be useful when installing fence posts, gate posts, signs, supports and similar applications.
The calculator treats each hole as a cylinder and calculates the combined volume before adding the selected waste allowance.
Concrete Mix Calculator
Site mixed concrete is generally made from cement, fine aggregate such as sharp sand, coarse aggregate and water. The proportions used can vary depending on the required concrete specification and application.
The site mix calculator provides estimated quantities based on nominal cement, sand and aggregate ratios. It is intended to help with material planning rather than replace a specified concrete mix design.
Concrete Mix Ratios
Common nominal ratios used for general concrete work include combinations such as 1:2:3 and 1:2:4, representing cement, sand and coarse aggregate. The appropriate ratio depends on the intended application and required performance.
For structural work, the required concrete specification should come from the project requirements rather than being selected solely from a nominal mix ratio.
Types of Ready Mix Concrete
GEN 0 Concrete
GEN 0 is generally associated with non-structural applications such as blinding, kerbing and selected filling work where a structural concrete specification is not required.
GEN 1 Concrete
GEN 1 is a general-purpose non-structural concrete specification used for selected light-duty construction applications.
GEN 2 Concrete
GEN 2 is used for selected domestic and light-duty concrete applications where its specification is appropriate.
GEN 3 Concrete
GEN 3 is a general-purpose concrete specification used for a range of reinforced and unreinforced applications where specified.
C20/25 Concrete
C20/25 is a commonly specified concrete strength class used across a range of domestic and general construction applications. The correct application depends on the project specification and exposure conditions.
C25/30 Concrete
C25/30 is a higher concrete strength class commonly specified for selected heavier-duty domestic and general construction applications.
C28/35, C30/37, C32/40 and C35/45
Higher concrete strength classes are available for applications requiring greater specified strength. The correct strength class should be selected from the structural or project specification rather than simply choosing the highest available grade.
Fibre Reinforced Concrete
Fibre reinforced concrete incorporates fibres into the concrete mix. It can be used for selected slabs, floors and other applications where the specified fibre system is suitable. Fibre reinforcement should not automatically be considered a replacement for designed structural reinforcement.
PAV1 Concrete
PAV1 is associated with paving applications and environments where resistance to freeze/thaw conditions is relevant. The correct specification should be confirmed for the intended external application.
How Much Concrete Is in a Cubic Metre?
One cubic metre of concrete is equivalent to 1,000 litres. Ready mix concrete is normally ordered in cubic metres, making the m³ calculation the most useful measurement when arranging a ready mix delivery.
The amount of raw material required to produce one cubic metre of site mixed concrete is not simply one cubic metre of cement, sand and aggregate. The calculator therefore applies a dry-volume allowance when estimating individual material quantities.
Why Add Waste to a Concrete Calculation?
Theoretical dimensions rarely match the exact quantity required on site. Excavations can vary in depth, surfaces can be uneven and a small amount of concrete can be lost during mixing, transport and placement.
For this reason, the calculator allows a selectable waste allowance. The appropriate allowance depends on the project and site conditions.
Ready Mix Concrete or Site Mixed Concrete?
For larger concrete pours, ready mix can reduce the amount of on-site mixing and handling required. It can also make it easier to place a substantial quantity of concrete within a short period.
For smaller jobs, site mixing may be practical where suitable equipment, labour and storage space are available. The most suitable approach depends on the volume required, access, labour, delivery arrangements and project requirements.
Concrete Calculator FAQs
It estimates the volume of concrete required for common projects including slabs, driveways, patios, paths, foundations, garage floors, pad foundations and post holes.
Ready mix concrete is normally measured and ordered in cubic metres. One cubic metre equals 1,000 litres.
Multiply the slab length by its width and thickness, using metres for all three measurements. The result is the volume in cubic metres before waste is added.
A small allowance is commonly useful to account for variations between calculated dimensions and the actual quantity required on site. The calculator allows you to select 0%, 5%, 10% or 15%.
The appropriate ready mix depends on the application, required strength, exposure conditions, reinforcement and project specification. The calculator provides guidance only and should not replace a structural specification.
Yes. Select Post Holes and enter the number of holes, diameter and depth. The calculator will calculate the approximate combined volume.
Yes. Select Site Mixed Concrete to calculate estimated quantities of cement, sharp sand and coarse aggregate based on the selected nominal mix.
No. It is a material estimation tool. Structural foundations, reinforced concrete and load-bearing applications should be designed and specified by a suitably qualified professional.