Why use a dry volume factor for concrete?

Dry ingredients contain voids. A dry volume factor accounts for compaction and shrinkage when cement, sand, aggregate and water are mixed.

Can this concrete calculator replace structural design?

No. It is for material estimation and planning. Structural grade, reinforcement and code requirements should be checked by a qualified professional.

Interactive estimation tool

Concrete Slab Calculator for Cement, Sand and Aggregate

Calculate concrete slab volume, dry mix, cement bags, sand, aggregate and waste allowance for construction material estimates.

Estimation Inputs

Enter measurements in the selected display units. The calculator converts them to canonical formula units before running the estimate.

Slab Floor Area

m²

Surface area of the slab.

Slab Thickness

Concrete pour thickness.

Cement Ratio

parts

Cement proportion in the mix.

Sand Ratio

parts

Sand proportion in the mix.

Aggregate Ratio

parts

Aggregate proportion in the mix.

Dry Volume Factor

coef

Compaction and shrinkage factor.

Waste Margin

Allowance for spill and site loss.

Cement Bag Weight

Weight of one cement bag.

Pricing & Rates

Prices are editable per estimate. Regional settings only provide starting rates, tax and currency labels.

Material Unit Price

AED

Price per purchase unit used by this calculator.

Labor Unit Rate

AED

Applied to the estimated purchase quantity.

VAT Tax Percent

Use 0 if tax is not applicable.

Estimate Outcome

Create a project and room first, then return here to attach this estimate to the BOQ.

Calculation guide and formulas

Use this concrete slab calculator to estimate wet volume, dry concrete mix volume, cement bags, sand and aggregate for slabs, footings and small pours.

Wet Volume = Area × Thickness; Dry Volume = Wet Volume × Dry Volume Factor

Worked example

A 100 m² slab with 0.1 m thickness needs 10 m³ wet concrete. With 5% waste and a 1.54 dry factor, dry volume is 16.17 m³. For a 1:2:4 mix, cement is about 2.31 m³ or 67 bags.

Frequently asked questions

Q: Why use a dry volume factor for concrete?
A: Dry ingredients contain voids. A dry volume factor accounts for compaction and shrinkage when cement, sand, aggregate and water are mixed.
Q: Can this concrete calculator replace structural design?
A: No. It is for material estimation and planning. Structural grade, reinforcement and code requirements should be checked by a qualified professional.