Calculate your result
Quick answer
A hypothetical 40 m² floor at 40 mm average thickness is 1.6 m³ before allowance. A chosen 10% adds 0.16 m³. Material bags need the confirmed mix or exact complete-product consumption; these dimensions do not specify a suitable screed.
How it works
Use the Screed Calculator South Africa to estimate installed volume from floor area and average thickness. Choose site-mixed cement and sand, a complete bagged product using its own data, or a volume-only supplied screed quote.
Formula
Installed m³ = net floor m² × average thickness in mm ÷ 1000. Apply one extra allowance. Site mix uses entered dry-volume assumptions; complete product bags use declared kg/m²/mm or finished litres per bag.
Assumptions and common mistakes
Check units, input values and the method before relying on an estimate. Review the existing tool notes and official sources below.
Formula
Installed m³ = net floor m² × average thickness in mm ÷ 1000. Apply one extra allowance. Site mix uses entered dry-volume assumptions; complete product bags use declared kg/m²/mm or finished litres per bag.
| Method | Calculation basis |
|---|---|
| Installed volume | Net m² × average mm ÷ 1000 |
| Site mix | Adjusted m³ × entered dry factor; split cement:sand |
| Product consumption | m² × mm × declared kg/m²/mm × allowance |
| Product yield | Adjusted finished litres ÷ declared L/bag |
| Purchase | Round bags/packs or entered volume increment |
How much screed do I need?
Enter a known net floor area or identical rectangles with total deductions. Multiply area by the specified average thickness in metres. A known net installed volume can also be entered; the tool derives an equivalent area from the chosen average thickness for area-based consumption and labour. Known area and volume already exclude deductions, so those inputs are not reduced again.
Screed calculator m² to m³
Area alone does not give volume. A hypothetical 40 m² at 40 mm is 40 × 0.04 = 1.6 m³. At 10% extra allowance, the material target is 1.76 m³. Measure uneven floors or zones with different depths separately; one nominal thickness may not represent low spots. The thickness is an entered project specification, not a recommendation.
Sand and cement screed calculator
Site-mix mode applies one allowance to volume, multiplies by the entered dry-material factor and splits the result by cement:sand parts by volume. It converts the cement portion to mass using entered loose bulk density, then rounds to the actual cement bag mass. The defaults 1:4, 1.33 and 1440 kg/m³ are editable arithmetic examples, not a mix design or guaranteed yield.
Sharp sand, dry mixes and sand delivery
Use the sand grading, cleanliness, moisture and batching basis specified for the actual system. A search term such as sharp sand does not establish a local aggregate specification. The model reports sand on the entered bulk-volume basis; it does not automatically convert to loose-delivered volume or tonnes. Dry-packed cement screed is not the same as a dry-board floor system, which this tool does not calculate.
Self levelling screed calculator
Choose complete product mode and enter either declared dry consumption in kg/m²/mm with bag mass, or declared finished litres per bag. These are different data bases and are not inferred from a brand name. Consumption per millimetre is multiplied by your average thickness; verify that the product permits that thickness and application. No cement or sand is added to a complete bagged product unless its instructions specify it.
Liquid screed and volume quotes
Volume-only mode reports installed volume with one allowance and an optional supplier order increment. A supplied liquid or flowing screed can have its own binder, specification, minimum order and pump arrangements. This calculator does not infer its ingredients, strength or bags. Enter a confirmed quote per ordered m³ and separate charges only when they are not already included.
Tile screed, primer and readiness
A screed quantity does not establish bonded, unbonded or floating construction, structural adequacy, minimum thickness, primer, reinforcement, joints or underfloor-heating requirements. A levelling compound may be an underlayment rather than a final wearing surface. Follow the exact substrate and flooring system. Drying, curing and readiness for tiles, vinyl or other finishes need product instructions and any required site checks, not a universal days-per-mm rule.
Cashbuild comparisons and quoted costs
99tools is independent of Cashbuild and manufacturers. Match the exact product, area, average depth, allowance, consumption, bag size and pack rounding. Enter full purchased bag prices, site sand on the same volume basis, or supplied screed per ordered m³. Labour uses net floor area for the agreed scope. No extra VAT is added; zero-price lines remain unpriced. This page focuses on South Africa and does not substitute UK product data or prices.
Save the screed calculation
Copy or print the result, or download the CSV snapshot after calculating. The file records quantities and entered costs; it is not an Excel workbook with live formulas or a screed design. Calculate different products or depths separately and confirm the complete specification and order with the supplier.
Reviewed by the 99tools team. Editorial and corrections policy.
Related floor and material tools
- Sand and Cement Calculator South Africa
- Floor Tile Calculator South Africa
- Concrete Slab Calculator South Africa
Screed planning guides
Frequently asked questions
How do I calculate screed from m²?
Multiply net floor area by specified thickness in metres to obtain installed m³. Apply one allowance before material and purchasing calculations.
How many self levelling screed bags do I need?
Use the exact product kg/m²/mm and bag mass, or declared finished litres per bag. Include one allowance, then round whole bags and purchase packs.
Is there one sand and cement ratio for every screed?
No. Confirm the specified mix and yield. The site-mix defaults are editable arithmetic examples.
Can I enter a known volume in m³?
Yes. Enter net installed volume before allowance and the specified average thickness. The tool derives equivalent area for relevant consumption and labour.
Does the tool choose a suitable screed thickness?
No. Thickness, construction type, substrate and product limits must come from the actual system specification.
Is this the Cashbuild screed calculator?
No. 99tools is independent. Use the exact selected product and quote to compare like-for-like estimates.
Does it calculate dry-board screed flooring?
No. Site-mixed dry-packed screed and dry-board floor systems are different quantity methods.
Related calculators
Sand and Cement Calculator South Africa
Estimate cement bags and sand for plaster, screed or brickwork from area, wet volume or brick count. Enter your mix ratio, assumptions and quoted prices.
Concrete Slab Calculator South Africa
Calculate slab concrete volume, premix bags or quoted costs from rectangles, triangles, circles or known area. Check sub-base volume and rectangle diagonals.
Floor Tile Calculator South Africa
Calculate floor tiles and full boxes in m² or square feet. Record your pattern, choose waste and estimate costs from current South African quotes.
Brick Calculator South Africa
Use this brick calculator for South Africa to estimate stock or face bricks from wall sizes, openings, mortar joints and waste. Add unequal wall sections.
Helpful guides
Floor Screed: Area, Thickness and Volume
Convert measured floor area and average depth to installed screed volume, then use the correct material and quotation basis.
Self-Levelling Screed Bags and Consumption
Use the exact levelling product consumption, bag size and permitted thickness before rounding a purchase to whole bags or packs.