Calculator
Sand, screed and gravel calculator
For a sand and cement screed, area × depth gives the volume; allow about 1.6 tonnes of sharp sand per cubic metre and cement at your mix, typically 1:4. For gravel, allow about 1.5 tonnes per cubic metre.
Enter your sizes, see the materials and a diagram, then send the list for a delivered price.
Quantities are estimates using standard UK rules of thumb and are shown with their working. We check them against your job before we price anything.
How the calculation works
- Volume = area × depth
- Screed dry volume ≈ volume × 1.25; cement = dry ÷ (1 + sand parts)
- Sharp sand = (dry volume − cement) × 1.6 t per m³; gravel ≈ 1.5 t per m³
Worked example
A 20 m² floor at 65 mm: 1.3 m³. At 1:4 with a 1.25 dry factor, about 0.33 m³ of cement (19 bags) and about 2.1 tonnes of sharp sand.
What to order with it
- Building & Sharp Sand: Soft building sand, sharp sand and plastering sand.
- Cement: 25 kg bags of general-purpose and rapid-set cement.
- Ballast & Gravel: All-in ballast, shingle, pea gravel and decorative stone.
Quantities are estimates. Pack sizes, bag weights and coverage vary by manufacturer; we confirm them on your quote.
Questions
What is the difference between building sand and sharp sand?
Building (soft) sand is fine and makes smooth mortar for laying bricks. Sharp sand is coarser, drains better and is used in concrete, screeds and paving beds.
How many bags of cement for 1,000 bricks?
At a 1:4 mortar mix, about 8 to 9 bags of 25 kg cement and roughly 1 tonne of building sand, allowing for waste.
Send your list, get a delivered price
Tell us what you need and where it is going. We check the quantities and come back with a delivered price before you commit.