Tile cartons needed = measured area, adjusted for the agreed cutting allowance, divided by coverage per carton, rounded up. Keep each tile product separate. This simple calculation prevents a surprisingly common mistake: ordering by the number of rooms rather than the area to be covered.
This worksheet is for quantity planning. For prices, labour and the complete installation bill, read our cost of tiling a house in Nigeria guide.
Step 1: measure the surface
For a rectangular floor, multiply length by width in metres. A 3 m by 4 m room has 12 square metres of floor area. Split an L-shaped room into non-overlapping rectangles, calculate each and add them together. Ask the installer to confirm measurements before ordering.
For walls, measure the length and intended tiled height of each section. Record doors, windows, niches and returns rather than applying an unexplained deduction. Your installer should establish which surfaces and cuts the order needs to cover.
Step 2: read the carton, not just the tile size
A 60 x 60 cm tile has a nominal face area of 0.36 square metres. Four such pieces give 1.44 square metres. But a carton might contain a different number of pieces. Use the manufacturer’s stated coverage for the actual product.
For example, the packaging table for this 60 x 60 cm product sold by Tiles Online Nigeria specifies four pieces and 1.44 square metres per carton. That is a product example, not a rule for every brand.
Step 3: agree an allowance
Cutting pattern, room shape, breakages and repair spares affect the quantity. Ask the installer to explain the allowance rather than treating a percentage found online as a universal rule. Diagonal layouts, small recesses and repeated edge cuts need attention before an order is finalised.
Keep cutting allowance and retained repair stock visible in the schedule. Otherwise two different people may each add a spare allowance without noticing.
Worked calculation: a 3 m by 4 m room
Assume 1.44 square metres per carton and an illustrative 10% allowance agreed for the calculation:
- Net area: 3 x 4 = 12 square metres.
- Area with allowance: 12 x 1.10 = 13.2 square metres.
- Cartons: 13.2 / 1.44 = 9.17.
- Round up to 10 cartons, covering 14.4 square metres.
Do not round down to nine: nine cartons cover only 12.96 square metres, below the example target. The difference between ordered coverage and net floor area includes both the chosen allowance and rounding; it is not all guaranteed spare stock.
Your room-by-room worksheet
| Field | What to record |
|---|---|
| Room and surface | Living-room floor, bathroom wall or other location |
| Product | Model, size, colour and finish |
| Net area | Installer-confirmed square metres |
| Allowance | Amount and reason |
| Packaging | Coverage per carton |
| Order | Whole cartons and resulting coverage |
| Cost | Cartons multiplied by current carton price |
Can you combine several rooms?
If the same product and batch will serve several rooms, calculate the overall requirement with the installer. Buying each small area independently can increase rounding. Do not combine different colours, sizes or finishes simply because they have the same price.
Before the supplier dispatches
Confirm that the quote uses the same unit as your calculation: square metres, pieces and cartons are not interchangeable. Ask about batch consistency, availability, delivery charges and the policy for unopened surplus cartons. Photograph the labels when materials arrive and keep the invoice.
What about skirting and stairs?
Give them separate measured lines. Skirting may be priced by length; stairs involve treads, risers, edges and cutting details. Do not assume the floor-area calculation includes either.
Next: put your quantities into the house BOQ worksheet so tile purchases and installation costs stay in the same project budget.
Reviewed 21 September 2026. This is an arithmetic worksheet, not a measured take-off for a specific building.
