Paint Calculator for Walls and Ceilings

Enter the room size, the number of doors and windows and the coats you plan to apply. The calculator subtracts openings, uses your paint coverage and tells you how much paint to buy and how many cans that is.

7-in-1 Pro Calculators

±1% Formula Accuracy

EN/RU/ES 3 Languages

Wall & Ceiling Paint Estimator

Room Dimensions

Room Length m

Room Width m

Wall Height m

Include Ceiling?

Doors, Windows & Coverage

Number of Doors

Number of Windows

Number of Coats

Paint Coverage m²/L

Container Size L

Price per Container $

Ceramic & Porcelain Tile Estimator

Surface Dimensions

Area Length m

Area Width m

Tile Size, Waste & Packaging

Tile Length cm

Tile Width cm

Grout Joint Gap mm

Cutting / Waste Reserve %

Coverage per Box m²

Price per Box $

Laminate & Hardwood Flooring Estimator

Room Floor Dimensions

Room Length m

Room Width m

Plank Size, Pattern & Packaging

Plank Length cm

Plank Width cm

Installation Pattern (Waste %)

Area per Pack m²

Price per Pack $

Underlayment Price per Area $

Wallpaper Rolls & Paste Calculator

Room Dimensions

Room Length m

Room Width m

Wall Height m

Roll Dimensions & Pattern Repeat

Roll Width cm

Roll Length m

Pattern Repeat (Offset) cm

Number of Doors

Number of Windows

Price per Roll $

Drywall Sheets, Framing & Screws Estimator

Structure Type & Sheet Dimensions

Construction Type

Single Sheet Area m²

Wall / Room Length m

Height (or Ceiling Width) m

Price per Drywall Sheet $

Concrete Slab, Screed & Bags Calculator

Slab / Pour Dimensions

Slab Length m

Slab Width m

Thickness / Depth cm

Reserve, Pre-Mix Bags & Pricing

Spillage / Grade Reserve %

Dry Mix Bag Size kg

Price per Bag $

Appliance Electricity Cost Calculator

Appliance Power & Usage Schedule

Appliance Name

Power Consumption W

Hours Used per Day h

Days Used per Month 1–31

Electricity Rate (per kWh) $

Live Calculation Summary

Paint required

9.1 L

4 cans × 2.5 L

Net Requirement 88% / 12% Reserve / Deductions

Compare Current Material Prices:

Home Depot Lowe's Amazon DIY Leroy Merlin

My Renovation Shopping List & Budget

Category / Calculation	Required Quantity	Estimated Cost

Frequently asked questions

How much paint do I need per square meter?

One liter of typical interior paint covers about 8–12 m² per coat (roughly 350–400 sq ft per gallon). Check the coverage printed on the can and enter it in the calculator for an exact result.

How many coats of paint should I apply?

Two coats give an even color and good durability on most walls. Use three coats when covering a dark color with a light one, or when painting raw plaster or drywall without a primer.

Should I subtract doors and windows from the wall area?

Yes. A standard door is about 1.9 m² and a window about 1.5 m². Subtracting them saves paint, but keep a 5–10% reserve for touch-ups and uneven absorption.

How much extra paint should I buy?

Buy about 10% more than calculated, and buy all cans from the same batch so the shade matches. Rough or porous surfaces such as fresh plaster can absorb noticeably more paint.