How to use it
- Enter project length and width in metres.
- Input slab length and width in millimetres.
- Set your wastage & cuts allowance percentage.
- Read the net and total slab counts plus area results.
What it does – The Paving Slabs Calculator turns your project dimensions and slab size into a clear purchase list. Enter the length and width of the area in metres, the slab dimensions in millimetres, and a wastage percentage for cuts and breakage. The tool converts slab size to square metres, divides the total project area by that figure, and then adds the waste factor to show how many slabs to order.
Why it matters – Ordering too few leaves gaps; ordering too many wastes money and storage space. The result shows the exact net slabs needed, the total including allowance, and the overall area covered, so you can budget confidently and place an accurate order. The Total slabs needed includes the waste percentage, while Exact slabs needed is the net count; both are displayed alongside the calculated total area and per‑slab area.
Pro tips
- Add a 5‑10% wastage allowance for typical cuts and breakage.
- Round up the final slab count to the nearest whole slab; you can’t order fractions.
- Order a few extra slabs for future repairs or pattern adjustments.
- Double‑check slab dimensions; a 10 mm error multiplies across the whole area.
Real-life examples
- A homeowner planning a 15 m² garden path wants to know how many 300 mm × 300 mm slabs to buy.
- A contractor estimating materials for a 200 m² commercial driveway needs precise slab quantities.
- A landscape designer preparing a quote for a client’s patio layout requires both net and total slab counts.
Case study
John, a landscaping contractor, entered a 30 m × 20 m patio, 600 mm × 600 mm slabs and a 5 % waste allowance. The calculator told him to order 1,111 slabs instead of his rough estimate of 1,050, preventing a costly shortfall and saving $200 on excess material.