Paint Calculator Widget | Calculator Campus

Start with the interior single-room flow. Switch modes for a ceiling, a whole exterior, or a primer coat; open advanced options for measured openings, extra material, a custom coverage rate, gables, or metric output.

Room or building length (required)

Room or building width (required)

Wall height (required)

Coats (required)

Surface / coverage (required)

Add openings, gables, and other options Hide additional options

Custom coverage rate

Opening area to subtract (sq ft)

Extra material allowance (%)

Number of gable ends

Gable base width

Gable peak height

Show metric (litres / m²)

Paint to buy

Enter a positive length, width, and height.

Paintable area 0 sq ft

Calculated paint 0.00 gal

Show calculation details Hide calculation details

Purchase breakdown

Whole gallons 0 gallons

Extra quarts None

How the purchase maps to cans —

Quart vs gallon A leftover of a quarter gallon or less tops up with one quart; more than that rounds up to the next full gallon, which costs less per unit than buying several quarts. The rounded-up leftover is your touch-up supply.

Calculation basis

Coverage rate used 350 sq ft/gal

Coats used 2 coats

Coverage basis Based on manufacturer data sheets: Sherwin-Williams SuperPaint PDS 101.11B lists 350–400 sq ft/gal; Benjamin Moore Regal Select N547 lists 400–450 (premium). This estimate used 350 sq ft/gal and the rate is editable.

Notes None