Tiles and boxes for any floor or wall, with wastage and the cost at your rate per square foot.
Running short of tiles is worse than buying a few extra: a later batch rarely matches in shade or size, and the floor shows it. Buying far too many ties money up in boxes that cannot always be returned.
A 4 m × 3 m room in 600 × 600 mm tiles: 12 m² ÷ 0.36 m² = 33.3 tiles; +10% = 37 tiles; boxes of 4 = 10 boxes (40 tiles, 155 sq ft). At ₹50 per sq ft: ₹7,750.
Lay out the tiles on the drawing first to place cuts at the walls, buy all boxes from one batch, and store 2–3% as spares for repairs.
Interior contractors take tile quantities room by room from a layout drawing and order each finish once, from one batch.
Rebota's BOQ holds the tile quantity per room, and purchase orders and store issues are checked against it so tiles are not over-bought or lost.