Ultimate Paint Calculator
Calculate exactly how much paint you need for any interior or exterior project with our precise estimation tool.
How to Calculate Paint Needed
Our paint calculator uses industry-standard formulas to provide accurate estimates for your painting projects. Here’s how it works:
Step 1: Calculate Surface Area
For a standard room: (Length + Width) × 2 × Height
Subtract the area of windows and doors (standard sizes: 15 sq ft per window, 20 sq ft per door)
Step 2: Adjust for Project Factors
Multiply by number of coats and texture factor
Add waste factor (typically 10%) to account for spills and touch-ups
Frequently Asked Questions
How much area does a gallon of paint cover?
Most quality paints cover between 350-400 square feet per gallon. However, coverage can vary based on surface texture, paint type, and application method.
Should I buy extra paint?
Yes, we recommend purchasing 10-15% more paint than calculated. This accounts for touch-ups, mistakes, and future repairs. Having leftover paint with the same batch number ensures perfect color matching.
How does surface texture affect paint usage?
Textured surfaces like stucco or heavily patterned walls can require 5-20% more paint than smooth surfaces because the texture creates more surface area to cover.