Sand and Cement Calculator
Find how much sand and cement you need for brick or block mortar, or a floor screed.
Measure your job
Your answer
For about 450 bricks (single brick wall), mixed 1 : 5.
Bulk bags are 800 kg. Bags are rounded up.
This answer is a guide. For footings, walls or anything that holds weight, check your local building rules or ask a builder or engineer.
What it costs
UK middle prices from October 2026, with VAT. Cement: £8.39 a 25 kg bag (7 prices from 3 sellers). Bulk bags: £75, building sand £67.35 (3 sellers each). Few prices, so treat them as a rough guide.
Quick answers
- 1,000 bricks at 1 : 5
- About 1.0 tonne of building sand and 6 bags of cement.
- Bricks and blocks per m²
- About 60 bricks in a single brick wall, and 120 in a double wall. About 9.88 blocks.
- Screed mix (BS 8204)
- 1 : 4 cement to sharp sand by weight, says the MPA. It can go from 1 : 3 to 1 : 4.5.
- Screed, 10 m² at 50 mm (1 : 4)
- About 8 bags of cement and 800 kg of sharp sand.
How to work it out
- Measure the wall or floor in metres. Multiply length × height (or width) for m².
- For a single brick wall, multiply by 60 to get bricks.
- Allow about 1 kg of building sand for each brick.
- For a 1 : 5 mix, add 150 kg of cement for each tonne of sand.
- Divide the cement by 25 for bags. Round up.
1,000 bricks × 1 kg = 1,000 kg of sand
1.0 tonne × 150 kg = 150 kg of cement
150 ÷ 25 → 6 bags
Sand and cement for bricks
The Brick Development Association and the Mineral Products Association (MPA) are trade bodies. Both say a tonne of mortar lays about 1,000 bricks. So we allow about 1 kg of building sand per brick.
The MPA gives kg of cement for each tonne of lime and sand, by mix group. We match those groups to plain sand mixes and work out the bags. Where it gives two figures, we use the higher one.
| Mix | Cement | 25 kg bags (our sum) | Class |
|---|---|---|---|
| 1 : 3 | 250 kg | 10 | M12 |
| 1 : 4 | 190 kg | 7.6 | M6 |
| 1 : 5 | 150 kg | 6 | M4 |
| 1 : 6 | 150 kg | 6 | M4 |
Classes are from Heidelberg's cement data sheet.
Which mix?
Gilmore Building Supplies says 1 : 5 is a common mix for bricks. Screwfix says 1 : 4 suits standard walls. For a wall that holds weight, check your local building rules or ask a builder or engineer.
A merchant's check
Travis Perkins allows about 120 kg of cement per 1,000 bricks, at 1 : 5. It adds 0.4 m³ of sand, which weighs about 0.6 tonnes. We allow 150 kg of cement and 1.0 tonne of sand, from the top of each range.
Sand and cement per m² of wall
| Wall | Building sand | Cement | Bricks or blocks |
|---|---|---|---|
| Single brick wall | 60 kg | 9 kg | 60 bricks |
| Double brick wall | 131 kg | 19.6 kg | 120 bricks |
| 100 mm blocks | 19 kg | 2.9 kg | 9.88 blocks |
Bricks per m² from Travis Perkins, blocks from Kilsaran. No extra added.
We worked out the double wall and block figures. Blue Circle and Kilsaran give the mortar. For the sand in it, we use the MPA's lime and sand figure. The MPA has none for plain sand and cement.
Makers disagree on blocks. Blue Circle says 1 m³ of mortar lays about 1,500 blocks. Kilsaran, an Irish maker, says about 800. We use Kilsaran's, so you are less likely to run short.
Sand and cement for a floor screed
BS 8204 is the British Standard for screeds. The table shows its main mix and both limits, by weight, as the MPA gives them.
| Thickness | 1 : 4 | 1 : 3 | 1 : 4.5 |
|---|---|---|---|
| 40 mm | 16 + 64 | 20 + 60 | 14.5 + 65 |
| 50 mm | 20 + 80 | 25 + 75 | 18.2 + 82 |
| 65 mm | 26 + 104 | 32.5 + 98 | 23.6 + 106 |
| 75 mm | 30 + 120 | 37.5 + 113 | 27.3 + 123 |
By weight, with no extra. 40 mm · bonded, 50 mm · unbonded, 65 mm · floating, 75 mm · over underfloor heating.
How we got these figures
No UK source we found gives this for screed you mix yourself.
Bagged mixes from Kilsaran and Heidelberg use about 1.82 to 1.96 kg per m² for each mm. Mapei's goes up to 2 kg. We use 2 kg, that top figure, and split it by your mix.
Before you buy
- Extra: we found no UK figure for extra mortar or screed. Our figures use the top of each range, so the calculator starts with none.
- Prices, with VAT: cement about £8.39 a bag, building sand £67.35 and sharp sand £75 a bulk bag. Each comes from only 3 sellers, so treat them as a rough guide.
Questions people ask
How much sand and cement do I need for 1,000 bricks?
For a single brick wall at 1 : 5, allow 1.0 tonne of building sand. Add 150 kg of cement, which is 6 bags of 25 kg.
How many bags of cement to a tonne of sand?
From MPA figures, we work out 10 bags of 25 kg for 1 : 3. At 1 : 5, it is 6 bags.
How many bulk bags of sand for 1,000 bricks?
About 1.25 bulk bags of 800 kg, which means buying 2. Heidelberg's building sand sheet puts one bulk bag at about 900 bricks.
How much sand and cement per m² of brickwork?
For a single brick wall at 1 : 5, about 60 kg of sand and 9 kg of cement. A double wall needs about 2.2 times as much.
How much sand and cement for 100 blocks?
About 193 kg of building sand and 29 kg of cement, at 1 : 5. That is 2 bags of 25 kg, worked out from Kilsaran's and the MPA's figures.
How many bricks will a 20 kg bag of mortar lay?
About 19, says Heidelberg Materials, for its 20 kg bagged mortar mix. So 1,000 bricks take about 53 bags. The calculator shows this for single brick walls only.
How much sand and cement do I need for a floor screed?
Each m² at 50 mm and 1 : 4 takes about 20 kg of cement. Add about 80 kg of sharp sand.
How thick should a floor screed be?
We use 40 mm for bonded, 50 mm for unbonded and 65 mm for floating screeds, from the MPA. For a screed over underfloor heating, we use Tarmac's 75 mm.
Where our numbers come from
- Screed: Tarmac Truscreed data sheet (weight once dry; thickness over underfloor heating)
- Sand per 1,000 bricks: Brick Development Association, Mortar for Brickwork
- Bricks per tonne: Mineral Products Association Mortar Data Sheet 01
- Cement per tonne of sand: Mineral Products Association Mortar Data Sheet 04
- Screed mix and thickness: Mineral Products Association Mortar Data Sheet 22
- Mortar mixes: Heidelberg Multicem data sheet
- Bricks per m² and 1:5 mortar: Travis Perkins brick calculator
- Mix ratios and cement per bulk bag: Gilmore Building Supplies guide
- Mortar mix for walls: Screwfix guide to making mortar (4 to 1)
- Mortar per brick: Blue Circle Quality Assured Mortar data sheet
- Ready-mixed mortar bags: Heidelberg Sand & Cement Mortar data sheet (20 kg lays about 19 bricks)
- Mortar per block: Kilsaran K-Spread mortar flyer (Ireland)
- Blocks per m²: Kilsaran block calculator (9.88)
- Screed per m²: Kilsaran KPRO Floor screed (about 1.95 kg per m² per mm)
- Screed per m²: Mapei Topcem Pronto data sheet (18–20 kg per m² per cm)
- Bricks per bulk bag: Heidelberg building sand data sheet (about 900)
- Mix ratios and 25 kg bags: Heidelberg General Purpose cement data sheet
- Cement price: the middle of 7 prices from 3 UK sellers (25 kg, Oct 2026)
- Bulk bag prices: the middle price from 3 UK sellers each (Wickes, Tippers, Lawsons; Oct 2026)
- Sand weight: Wickes sharp sand bulk bag (800 kg covers 10.6 m² at 50 mm)
Made by BuildersCount. Last checked 3 Oct 2026.
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