Screed calculator
Work out the volume of screed for a floor from its area and total depth. Free, no sign-up, and nothing you enter leaves this page.
Result
Enter the area and total depth, then select Calculate quantity.
Method
area (m²) × total depth (mm) ÷ 1000 = volume (m³)
Results are rounded to 3 decimal places. This is a geometric volume for one uniform depth, not an order quantity, price or depth recommendation. Confirm the quantity to order with the screed supplier or installer.
How screed volume is calculated.
area (m²) × total screed depth (mm) ÷ 1000 = volume (m³)
Dividing millimetres by 1,000 converts the depth to metres, so square metres × metres gives cubic metres.
Worked example
50 m² × 65 mm ÷ 1000 = 3.25 m³
3.25 m³ × 1.05 (5% allowance) = 3.4125 m³, shown as 3.413 m³
The 5% here only illustrates the arithmetic. It is not a recommended allowance.
Measuring area and depth.
Floor area
- For a rectangular room, multiply length by width in metres.
- For an L-shaped or irregular floor, split it into rectangles, work out each one and add them together.
- For several rooms at the same depth, add the room areas.
- Where depth changes between areas, run the calculator for each area separately and add the volumes.
Total screed depth
Use the full depth from the surface the screed sits on to the finished screed level. Over underfloor heating, that is pipe diameter plus pipe cover — not the cover alone. The depth itself depends on the build-up, system and manufacturer requirements; see the screed depth guide and screed over underfloor heating.
Volume is not the order quantity
The geometric volume assumes a perfectly even base at one depth. Base levels, system type and delivery method all affect what is actually ordered, so the screed supplier or installer should confirm the final quantity. For what affects the cost of a floor, read the screed cost guide.
Screed calculator questions.
How do I calculate how much screed I need?
Multiply the floor area in square metres by the total screed depth in millimetres, then divide by 1,000. The answer is the geometric volume in cubic metres. For example, 50 m² at 65 mm is 50 × 65 ÷ 1,000 = 3.25 m³.
Is total screed depth the same as pipe cover over underfloor heating?
No. Pipe cover is only the screed above the top of the pipes. Total depth runs from the surface the screed is laid on to the finished screed level, so it includes the pipe diameter as well as the cover. Use total depth in the calculator, and confirm the minimum cover with the screed and heating system manufacturers.
Why is the order quantity different from the calculated volume?
The calculator gives a geometric volume for a perfectly flat floor at one depth. Real floors vary in level, and pumping, waste and product behaviour differ between systems. Any allowance you add is your own assumption. The supplier or installer should confirm the quantity actually ordered.
What allowance should I add?
The calculator does not recommend one; it defaults to 0%. The right figure depends on how level the base is, the screed system, the delivery method and the supplier. Ask the supplier or installer for the allowance they use for your floor.
What if different rooms have different depths?
Calculate each area that has its own depth separately and add the volumes together. Averaging depths across a whole floor can hide significant differences in quantity.
Does the calculator give a price or tell me what depth to use?
No. It only converts area and depth into volume. It does not use material rates, densities or bag weights, and it does not recommend a thickness. For a price, request an indicative estimate or send drawings for a commercial quotation.
Need the floor priced?
The calculator gives a volume only. For a price, send the known area and depth for an indicative estimate, or upload drawings and the floor build-up for a commercial quotation.