Practical guides
Measure well before estimating a project
Short, practical guidance for recording the right dimensions, choosing a sensible allowance and turning a result into a purchase quantity.
Practical guides — from calculation to construction
Three checks before estimating materials
A useful estimate starts with a net measurement, consistent units and an allowance suited to the job.
Measure an irregular area
Split an irregular room into rectangles, calculate each area and add them together. Subtract only openings that will genuinely remain uncovered.
CalculateAllow for cuts and waste
Add the allowance after calculating the net area. A straight layout usually creates less waste than a diagonal layout or a room with many corners.
CalculateTurn depth into volume
For gravel, concrete or a sub-base, multiply area by depth in metres. Keep the loose depth separate from the compacted finished depth.
CalculateTurn the result into a shopping list
Keep the assumptions with the estimate: finished dimensions, depth, product size, pack size and allowance. A changed price or measurement can then be updated without starting over.
- Use one unit throughout and convert millimetres or centimetres to metres before calculating volume.
- Round up to complete packs, bags, rolls or pallets rather than to the nearest mathematical unit.
- Check the manufacturer’s coverage, overlaps and installation requirements before ordering.