Wall Putty Calculator: kg, Bags and Cost per Sq Ft

Published putty coverage: read the coat basis

Birla White WallCare quotes 1.5–2 m²/kg and Asian Paints SmartCare Waterproof Wall Putty 1–1.5 m²/kg, both for two coats together. Lower coverage means more kg for the same wall.

Birla’s figure is for a smooth mortar wall; Asian Paints’ is for rough masonry, up to 1.5 mm total in two coats (sheet VN17/11/2024). The surfaces differ, so this is not a ranking. For another product or your own trial patch, choose “Enter confirmed coverage” and give both the yield and its coat count. Sources checked 21 October 2026.

Measure room walls minus doors and windows

Inside wall area = 2 × (room length + width) × height − openings. Add length × width once if the ceiling also needs putty.

For the default 4 × 3 m room, 3 m high with 2 m² of openings: 2 × (4 + 3) × 3 − 2 = 40 m². Ticking the ceiling adds 4 × 3 = 12 m², giving 52 m². For walls of different sizes, switch to individual walls.

Measure only the faces you will finish. Putty on both sides of a wall means both faces; measure reveals and returns on their own. Floor area alone does not give wall area. For the plaster underneath, use the plaster calculator.

Worked examples: kg and whole bags

100 m² needs 50–66.7 kg of Birla White WallCare across its two-coat range, before any allowance.

1. At 2 m²/kg: 100 ÷ 2 = 50 kg. Order ceiling(50 ÷ 20) = 3 bags of 20 kg, or ceiling(50 ÷ 40) = 2 bags of 40 kg.
2. At 1.5 m²/kg: 100 ÷ 1.5 = 66⅔ kg. Order 4 bags of 20 kg, or 2 bags of 40 kg.
3. For the default room at 1.5 m²/kg: 40 ÷ 1.5 = 26⅔ kg. Order 2 bags of 20 kg, or 1 bag of 40 kg.

Buy one bag size, not both. Round up the total, not each wall. The allowance starts at 0%; add your own. One or three coats are scaled from the two-coat figure, which is only an estimate because coats differ in thickness.

Wall putty cost per sq ft from your rate

Putty material cost per sq ft = your ₹/kg rate × 0.046–0.062 kg, using Birla White’s two-coat coverage of 16.15–21.53 sq ft per kg. The calculator assumes no price; enter your own rate.

If the shop quotes a bag price, divide it by the bag weight to get ₹/kg, using the bag size you will buy. The calculator shows the cost of putty used and the cost of whole 20 kg or 40 kg bags. Labour, primer, paint, delivery and surface repairs are extra.

For paint litres and primer after putty, use the paint calculator. Do not use paint’s litres-per-coat coverage as putty’s kg coverage.