What are you building?
Pick the job. Each one opens the calculator that works it out.
- Laying a patio
- Pouring a concrete base
- Plasterboarding a room
- Laying a lawn
- Building a fence
- Laying decking
- Painting a room
- Tiling a wall or floor
- Laying flooring
- Building a garden wall
- Planning a garden
- Spreading gravel or a path
- Hanging wallpaper
See all 19 calculators → Project Packs: calculate, plan, buy, build →
Plan the whole job
The Project Planner is the front door: describe the job, and it gathers every material into one list.
Project Planner — one job, one shopping list
Describe the job in a few words. The planner points you at the right calculator, asks the one or two measurements that calculator needs, and merges every result into a single project shopping list. It invents nothing: every figure comes from the calculator it sent you to, and the project is held in your browser only.
Worked example — a 6 m × 4 m patio
Inputs, so you can repeat it: patio 6.00 m × 4.00 m · slabs 600 × 600 mm · joints 10 mm · MOT Type 1 sub-base 100 mm compacted · sharp sand bedding 40 mm · waste 10% (the site's DIY preset). Every figure below is the output of that calculator's own engine.
- Paving area
- 24.0 m²6.00 m × 4.00 m
- Slabs per row
- 10 across × 7 down600 × 600 mm with 10 mm joints
- Slabs before waste
- 70Plus 10% for cuts and breakages
- MOT Type 1 sub-base
- 4.32 t24.0 m² × 100 mm × 1.8 t/m³
- Sharp sand bedding
- 1.54 t24.0 m² × 40 mm × 1.6 t/m³
Your shopping list
| Material | Quantity | Notes |
|---|---|---|
| Paving slabs 600 × 600 mm | 77 slabs | 10 × 7 = 70 plus 10% for cuts. |
| MOT Type 1 sub-base | 4.32 tonnes | ≈ 6 × 850 kg bulk bags at 100 mm compacted. |
| Sharp sand (bedding) | 1.54 tonnes | ≈ 62 × 25 kg bags, or 2 bulk bags, at 40 mm. |
| Jointing sand or paving grout | estimate only | Check the manufacturer's coverage for your joint width. |
| Edge restraint / kerb and concrete haunch | 20 m | The open perimeter — 20.0 m here. An unrestrained edge lets the paving spread. |
Sub-base depth is the one number people get wrong. 100 mm compacted is fine for a footpath or light patio; go to 150 mm for anything a car will park on. Work the rest of the job out on the paving calculator.
Popular calculators
View all 19 calculators →- Plasterboard
Plasterboard calculator
Sheets, screws and scrim tape from your room size.
- Paint
Paint calculator
Litres needed, and which tins to actually buy.
- Turf
Turf calculator
Rolls of turf, plus topsoil if you need it.
- Paving
Paving calculator
Slabs, sharp sand and MOT Type 1 sub-base.
- Concrete
Concrete calculator
Cubic metres, or cement, sand and aggregate.
- Gravel
Gravel calculator
Tonnes or bulk bags for a drive or path.
All 19 calculators
Grouped by the part of the job they belong to. Every tool is also in the menu above, and the search box finds them by name.
Walls, floors and interiors
- Plasterboard
Plasterboard calculator
Room size, walls and ceiling, board size and waste allowance → sheets, screws and scrim tape.
- Paint
Paint calculator
Wall area or full room dimensions, coats and coverage → litres needed, and which tins to buy.
- Brick
Brick calculator
Wall area and brick size → bricks, blocks and the mortar to lay them.
- Wallpaper
Wallpaper calculator
Wall run, drop height, roll size and pattern repeat → how many rolls to order.
- Insulation
Insulation calculator
Area and the coverage on a roll → how many rolls to order, with the waste allowance.
- Flooring
Flooring calculator
Room area and pack coverage → packs, underlay and waste.
- Carpet
Carpet calculator
Room size, pile direction and roll width → square metres and carpet cost.
- Worktop
Worktop calculator
Run lengths and worktop size → how many lengths to order, and the offcut left.
- Tiles
Tile calculator
Surface size, tile size and joint → boxes of tiles, adhesive, grout and spacers.
- Skirting
Skirting board calculator
Room perimeter, openings and stock length → how many lengths of board to buy.
Garden and landscaping
- Turf
Turf calculator
Lawn length and width, roll size and cutting allowance → rolls of turf, plus topsoil if you need it.
- Topsoil
Topsoil calculator
Border or lawn size and depth → bulk bags or tonnes of topsoil.
- Decking
Decking calculator
Deck size, board width and gap → boards, joists and fixings.
- Fence
Fence calculator
Run length and panel size → panels, posts, gravel boards and Postcrete.
- Shed base
Shed base calculator
Shed size and depths → the concrete, the MOT Type 1 sub-base or the paving slabs it takes.
Groundworks, paving and driveways
- Concrete
Concrete calculator
Slab or footing volume → cubic metres, or the cement, sand and aggregate to mix it.
- Paving
Paving calculator
Patio size, slab size and joint width → slabs, sharp sand and MOT Type 1.
- Gravel
Gravel calculator
Area and depth → tonnes or bulk bags, with the sub-base you need underneath.
- Mortar
Sand, cement and mortar calculator
Job type and mix ratio → sand, cement and water by the bag for pointing, bedding, screeds and render.
Why ProjectCalc?
Built for how a UK job actually gets ordered.
- Real quantitiesEvery answer is the unit you buy in: slabs, sheets, bags, tonnes, rolls — not just square metres.
- Clear mathsYour number comes with the working and a diagram of where it came from, so it can be checked.
- No sign-upOpen a calculator and start. No account, no email, no waiting.
- Private by defaultYour measurements stay on your device — nothing you type is uploaded, and there is no cookie banner. One cookieless visit counter counts page views; it never sees your figures. Read the privacy policy →
The waste and tolerance defaults are written out on the page as stated assumptions, not hidden in the engine — the DIY figure is the cautious one and every value can be typed over.
How the calculators work, and where the figures come from →
From measurements to buying
Three moves, and the order is right.
- Measure the area, run or room in front of you — in metres.
- Calculate the quantity, with the waste and tolerance the job really needs.
- Shopping list take the list to the merchant, or print it and hand it over.
How we got your number
Every answer shows its route — measurements, area, material coverage, waste, then the quantity to buy.
Guides
Each guide shows the worked example it used, so you can repeat it in the calculator.
All how-to guides →- Patio
How to calculate materials for a DIY patio
Slab counts on the module, MOT Type 1 sub-base, sharp sand bedding and jointing, with a worked 6 m × 4 m patio.
- Turf
Laying turf: rolls, cutting allowance and topsoil
Roll sizes, the cutting allowance and the topsoil a dressing needs, with a worked 12.5 m × 8.2 m lawn.
- Sub-base
How much sub-base do you need?
MOT Type 1 depth by use, the tonnage maths and the bulk-bag conversions, with worked patio and shed-base examples.
- Plasterboard
Plasterboard sheets for walls and ceilings
Wall and ceiling areas, the waste allowance, screws and scrim tape, with a worked 4 m × 3 m room.
- All guides
Every how-to guide on the site
What the guides are built on, what they are not, and the worked example behind each one.
Tools you may need
For the 6 m × 4 m patio above. A kit list, not a shopping list — nothing here is added to an order.
Don't forget — check before you order
- Sub-base: 4.32 t of MOT Type 1 — about 6 × 850 kg bulk bags, or loose. Check the lorry can reach the drop, and that you have somewhere to put it.
- Bedding sand: 1.54 t of sharp sand — about 62 × 25 kg bags, or 2 bulk bags. Keep it dry and covered.
- Edge restraint: 20 m — the open perimeter, plus a concrete haunch. Only the edges that meet soil or a drop need it, but an unrestrained edge lets the paving spread.
- Jointing sand or paving grout — the calculator returns this as an estimate only. Check the maker's coverage for a 10 mm joint.
- Weed-control membrane — optional, but a fabric layer under the sub-base is cheaper than lifting the patio later. No quantity is quoted for it.
- Spoil removal — the dug-out material has to go somewhere. Sort the skip before you dig, not after.
- Cutting — the right blade for the slab, and a water feed or dust control. The 10% allowance covers the cuts; it does not cover a broken pallet.
- Delivery and access — slabs, sub-base and sand in one drop is cheaper than three, if the driver can get in.
Estimates, not a quote. These figures are a planning aid from your own measurements, not a structural or professional specification. Check your supplier's current product data before ordering.
Start with the job you are actually doing
Describe it once, and the planner keeps the whole list together.