Construction & Building CalcyZone Calculator

Wall Paint & Primer Calculator

Calculate paint liters, primer, and wall putty required for room interior and exterior painting.

Unit Standard:

Waste Factor:5%

Currency:

Project Inputs

Length (meters)

Height (meters)

Live Estimation Summary

Visual Schematic (rectangle)

Estimated Material & Direct Cost₹3,390

Material Quantities & BOQ Breakdown

Item Material	Calculated Quantity	Standard Unit	Est. Unit Price	Subtotal (INR)

Engineering Disclaimer: CalcyZone construction estimations are provided for planning, budgeting, and educational purposes. Material specifications, load calculations, and structural designs must be reviewed by a licensed civil or structural engineer prior to construction.

Mathematical Formula

Paint Liters = Total Wall Area × Number of Coats / Coverage Rate per Liter

Overview & Explanation

Calculates exact liters of interior/exterior paint, primer, and wall putty for any room or building facade.

How It Works

Deducts openings (doors/windows) from gross wall area.
Multiplies net area by 2 coats and applies coverage constants.

Practical Applications

Room repainting
New house painting budget
Exterior weather coat estimation

How paint quantity is estimated

Paint needed = (paintable area × number of coats) ÷ coverage per litre. The paintable area is the total wall area (perimeter × height) minus doors and windows. A standard door is about 1.9 m² and an average window about 1.5 m². Coverage is printed on the tin; interior emulsions usually cover 10 to 14 m² per litre per coat on smooth, primed walls.

Rough, porous or freshly plastered walls absorb more paint, so use the lower end of the coverage range or apply a primer first.

Worked example

A room 4 m × 3.5 m with 2.8 m high walls has a wall area of 2 × (4 + 3.5) × 2.8 = 42 m². Subtract one door (1.9 m²) and two windows (3 m²) to get 37.1 m². Two coats at 12 m² per litre need 37.1 × 2 ÷ 12 = 6.2 litres, so buy two 4-litre tins or one 4-litre and one 2-litre tin plus a little spare.

Tips

Buy all the paint for one room from the same batch so the shade matches. Keep a small amount for touch-ups. Ceilings are calculated separately as length × width and usually need a dedicated ceiling paint.