Free MOT Type 1 calculator: enter your length, width and compacted depth to work out the tonnes of Type 1 sub base and how many bulk bags to order, with a compaction allowance built in.
Read the guide
Tools
Concrete Block Calculator: How Many Blocks Do You Need?
Free concrete block calculator for UK builders. Enter your wall length and height, subtract openings, and get the number of standard 440 x 215mm blocks you need, with wastage added.
Tools
Concrete Calculator UK: Cement, Sand and Ballast by the m3
Free concrete calculator for UK builders: enter your slab size and mix, and get cement bags, sharp sand and ballast in tonnes, plus total m3 for ready-mix.
Tools
Sand and Cement Calculator: How Much Do I Need?
Free sand and cement calculator for paving beds, patios, brickwork and screed. Enter your area and get sand in tonnes and bulk bags plus 25kg cement bags, with wastage.
Tools
Aggregate Calculator: Tonnes and Bulk Bags for Sub-base, Gravel and Sand (UK)
Free aggregate calculator (UK): enter length, width and depth, pick your material, and get the tonnes and bulk bags you need. Works as a sub base calculator and MOT sub base calculator.
Tools
Mortar Calculator UK: Sand and Cement for Brickwork, Blockwork and Patios
Free UK mortar calculator: work out the mortar, sand and cement you need by wall area or number of bricks and blocks, with a 10% wastage allowance built in. Includes a patio mortar mode.
Tools
Floor Joist Span Calculator (C24 & C16): Max Clear Span and Joist Count
Free floor joist span calculator for C24 and C16 timber: pick grade, joist size and spacing to get the indicative maximum clear span and the number of joists for your room. UK domestic floors.
Tools
Topsoil Calculator: How Much Topsoil Do I Need? (UK, m2 and Tonnes)
Free UK topsoil calculator. Enter your area in m2 and the depth in mm to get the volume in m3, the weight in tonnes, and the number of bulk bags you need.
Tools
Ballast Calculator: Ballast and Cement for a Concrete Mix
Free ballast calculator: enter your length, width and depth and get the ballast (tonnes and bulk bags) plus cement (25kg bags) for a shed base, footings or slab.
Tools
Gravel Calculator UK: Tonnes, Bulk Bags and 25kg Bags
Free gravel calculator (UK): enter your area in m2 or length x width plus a depth, and get tonnes, bulk bags and 25kg bags for 20mm gravel, with a 5% wastage allowance.
Tools
Brick Calculator UK: How Many Bricks and How Much Mortar Do You Need?
Free brick calculator for the UK: enter your wall size, subtract openings, and get the number of standard bricks you need plus a brick mortar estimate in sand and cement, with wastage added.
Concrete & Cement
How to Mix Concrete: UK Ratios, Method and Curing
A practical UK guide on how to mix concrete: the common cement, sand and ballast ratios, mixing by hand or by mixer, water content, slump, curing and the mistakes that weaken a pour.
Concrete & Cement
Concrete Cost UK: Ready-Mix Prices, Bagged Cost and Pump Hire
A plain-English UK concrete cost guide: ready-mix price per m3, minimum loads and part-load charges, the cost of mixing your own from bags, when ready-mix wins, and pump hire rates.
Aggregates & Sub-base
How to Lay an MOT Type 1 Sub-Base: Depths, Compaction and a Step-by-Step Method
A practical UK guide on how to lay an MOT Type 1 sub base for a drive, patio or shed base: excavation depth, geotextile membrane, spreading, compacting in layers with a wacker plate, and blinding.
Mortar & Render
Mortar Mix Ratio Guide: Bricklaying, Pointing, Blockwork and Render
A plain-English UK guide to the right mortar mix ratio for bricklaying, pointing, blockwork and render, including 4:1, 5:1 and 6:1 sand to cement, plasticiser and NHL lime mortars.
Bricks & Blocks
How Many Bricks Per Square Metre? UK Brick Estimating Guide
How many bricks per square metre for UK walls: 60 bricks per m2 for a single-skin half-brick wall and 120 for a one-brick wall, plus standard brick sizes, mortar joints, wastage and how to estimate a wall.
Bricks & Blocks
Concrete Blocks vs Bricks: A UK Buying and Comparison Guide
Concrete blocks vs bricks compared for UK builds: dense, lightweight and aircrete blocks against facing bricks on strength, insulation, cost and build speed, with real 2026 price ranges.
Timber & Steel
Floor Joist Sizes and Spans: A UK Guide to C16, C24 and Spacing
A practical guide to UK floor joist sizes and spans: C16 vs C24 grades, common sizes from 47x100 to 47x225, how 400, 450 and 600mm spacing changes the span, and why you should confirm against span tables or a structural engineer.
Concrete & Cement
How to Lay a Shed Base: Concrete, Paving Slabs and Plastic Grid Options
A practical UK guide on how to lay a shed base: concrete, paving slabs and plastic grid options, the right thickness, timber formwork, a ballast and cement mix, levelling and curing times.
Ordering building materials is where a lot of jobs lose money. Order short and you stop work for a second delivery. Order long and you are paying to cart away a pile of unused ballast. Build Journal exists to take the guesswork out of that first step: tell our calculators the size of the job and they give you the quantities in the units your merchant actually sells, bags, tonnes, cubic metres and packs.
Every calculator here uses the same UK trade ratios a good groundworker or bricklayer would use, and shows its working so you can sanity-check the number before you pick up the phone.
You do not need to know the maths, just the measurements. Most calculators ask for nothing more than a length, a width and a depth, then handle the conversions, densities and wastage allowance for you.
These tools come out of real UK building work, not a spec sheet. We check every formula against the densities, coverage rates and mix ratios used on site, and we add a sensible wastage margin so you are not caught short. They are estimates for planning, so always confirm the final order with your supplier, but they will get you close enough to budget and to buy with confidence.