Standard UK sizes · Metric & Imperial

How many bricks do you need?

Enter your wall dimensions and get an exact material list — bricks, mortar, sand, and cement — ready to order.

Wall Dimensions
metres
metres

1:4 is standard for most brickwork. Use 1:3 for engineering bricks or below DPC.

Deductions (optional)
no.
Waste & Costing
Wastage allowance
%
£

Typical UK range: £450–£900 per 1000. Leave blank to skip cost.

Your materials list
🧱

Enter your wall dimensions
and press Calculate

How much sand & aggregate do you need?

Calculate exact tonnes, bulk bags, or mini bags needed for any area and depth — sharp sand, building sand, gravel, MOT Type 1 and more.

Material Type
Area & Depth
m
m
mm

Typical depths: Patio sand bed 30–50mm · MOT sub-base 100–150mm · Building sand/holm sand 25–50mm

Bag Size Preference
Cost (optional)
£

Bulk bag prices: Sharp sand £55–£75 · Holm sand £50–£70 · MOT Type 1 £65–£85 · Gravel £70–£95

Wastage allowance
%
Your materials list
⛱

Choose your material, enter the area and depth, then press Calculate

How much concrete do you need?

Slabs, footings, paths and columns. Get exact volumes, site-mix quantities, or ready-mix lorry estimates.

Slab Type
Dimensions
m
m
mm

Typical depths: Patio 75–100mm · Garage floor 100mm · Driveway 150mm · Footings 200–400mm

Concrete Mix
Supply Method
Wastage allowance
%
Your materials list
🏗

Enter your slab dimensions
and press Calculate

Paving & driveway materials

Calculate slab or block counts and edging for any paving project.

Paving Type
Area
m
m
Slab / Block Size
Wastage allowance
%
Your materials list
🔲

Enter your paving area
and press Calculate

How much plaster do you need?

Calculate bags of finish coat, bonding, or sand-and-cement render for any room or wall area.

Plaster Type
Area
m
m
m
openings

Each opening deducted at approx 1.8m² (standard door size)

Cost (optional)
£

Typical UK prices: Thistle finish £10–£14 · Bonding £9–£13 · Sand &cement render from £5

Wastage allowance
%
Your materials list
🪣

Enter room dimensions
and press Calculate

How many concrete blocks do you need?

Standard block-on-edge walling or block-on-flat foundation courses — get block count, mortar, sand, and cement ready to order.

Laying Method

Standard method — block laid with the 215mm face vertical. Used for internal walls, cavity wall inner leaf, outbuildings.

Block Size
Wall Dimensions
m
m

For block-on-edge: height is the finished wall height.

Deductions (optional)
no.
Mortar Mix

1:4 is standard for blockwork above DPC. Use 1:3 for below-ground or structural work.

Waste & Costing
Wastage allowance
%
£

Typical UK prices: Standard 100mm £0.90–£1.40 · Dense £1.10–£1.60 · Jumbo from £1.80

Your materials list
🟫

Choose laying method, enter dimensions, then press Calculate

Common questions

Quick answers to the most searched construction material questions.

How many bricks do I need to build a wall?

A standard UK half-brick wall (102.5mm thick) uses approximately 60 bricks per square metre with a 10mm mortar joint. A full one-brick wall (215mm) uses around 120 bricks per m². Always add at least 10% for wastage and cutting. Use the Bricks & Mortar calculator above — enter your wall length and height, choose your brick size and wall type, and you'll get an exact figure including the sand and cement needed for the mortar.

How much MOT Type 1 do I need for a patio?

For a patio sub-base, allow 100–150mm of compacted MOT Type 1. As a guide, a 5×4m patio at 150mm depth needs around 4.5 tonnes — roughly 6 bulk bags. Add 10% for wastage and compaction. Select MOT Type 1 in the Sand & Aggregate calculator above and enter your area and depth for an exact bulk bag count.

How much MOT Type 1 do I need for a driveway?

A driveway sub-base typically needs 150–200mm of compacted MOT Type 1. A 5×3m driveway at 200mm depth requires approximately 4.5 tonnes before compaction — around 6 bulk bags. Allow 10–15% extra for wastage. Enter your exact driveway dimensions in the Sand & Aggregate calculator and select MOT Type 1 to get a precise quantity.

How much concrete do I need for a shed base?

A shed base is typically poured at 100mm depth. A 3×2.4m base needs approximately 0.72m³ of concrete. For a site mix at 1:2:4 that is roughly 6 bags of 25kg cement, 700kg of sharp sand, and 1,200kg of gravel. The Concrete Slab calculator above handles this — including ready-mix lorry estimates for larger pours.

How much sand and cement do I need for brickwork mortar?

For standard brickwork a 1:4 cement to building sand mix is typical. Expect to use roughly 0.5–0.7 bags of cement and 150–200kg of building sand per m² of half-brick wall. For engineering bricks or below-DPC work use a stronger 1:3 mix. BuildCalc calculates mortar quantities automatically alongside the brick count.

How many concrete blocks do I need to build a wall?

A standard 440×215×100mm concrete block covers approximately 0.1m² per block including a 10mm mortar joint — that's around 10 blocks per square metre. A 3m × 2.4m wall needs roughly 72 blocks. The Concrete Blocks calculator gives you exact quantities including mortar sand and cement, and handles block-on-flat foundation courses too.

How much render do I need for an external wall?

Standard two-coat external render is applied at 15–20mm total thickness. At 18mm, a 20m² wall needs roughly 0.36m³ of render mix — around 7–8 bags of cement and 500kg of sharp sand for a 1:4 mix. Use the Plaster & Render calculator and select your render type for a full materials breakdown including scratch coat and finish coat.

How do I calculate how much sharp sand I need for pointing?

For paving pointing, you typically need around 3–5kg of dry sand per m² for brush-in jointing sand, or a 1:4 cement and sharp sand mix at 10–15mm depth for mortar pointing. Enter your paved area in the Sand & Aggregate calculator and select Sharp Sand — it will tell you exactly how many bags or bulk bags to order.

How many bags of multi-finish plaster do I need per square metre?

Multi-finish is applied as a 2mm finish coat over a scratch coat or bonding plaster. At that thickness you'll use approximately 1.5–2kg per m², which works out to roughly one 25kg bag covering 12–15m². Coverage drops if you're filling uneven surfaces or applying slightly thicker. As a rule of thumb, divide your total wall area by 13 and round up to get the number of bags to order. Use the Plaster & Render calculator above — select Multi-Finish and enter your room dimensions for an exact bag count including wastage.

How much topsoil do I need for a new garden lawn?

For a new lawn from seed or turf you need a minimum of 100–150mm of good topsoil — 150mm gives the best results and root depth. At 150mm, a 10×5m garden needs approximately 7.5 tonnes of topsoil, which is around 9–10 bulk bags. If you're topdressing an existing lawn rather than starting from scratch, 10–20mm is enough — roughly 1 bulk bag per 40m². Select Topsoil in the Sand & Aggregate calculator and enter your garden dimensions and depth to get an exact figure.

Does block on flat give a stable wall?

Yes — block on flat is actually more stable than block on edge for the right applications. Laying a 440×215×100mm block with its 215mm face horizontal gives you a 215mm wide bed rather than the standard 100mm, which creates a much wider, lower centre of gravity. This makes it the preferred method for foundation courses below DPC, heavily loaded base courses, and wide infill beds where lateral stability matters. The trade-off is that each course is only 100mm tall (vs 215mm on edge), so it takes more courses to gain height — and it uses significantly more mortar, roughly 2.7× the mortar of standard block-on-edge laying. It is not typically used for full above-ground walls because of the extra material cost and slower build rate. The Concrete Blocks calculator handles both methods and will show you the mortar difference.