How much area does one gallon of paint cover?

One gallon of paint typically covers 350–400 square feet per coat. Coverage varies by paint type, surface texture, and application method.

How many coats do I need?

Most interior walls need 2 coats. Going from a dark to light color may require 3 coats. Always apply a primer coat when painting over a radically different color.

Should I account for windows and doors?

Yes. For each standard door subtract 20 sq ft and for each window subtract 15 sq ft from your total wall area before calculating gallons needed.

Paint Coverage Calculator Free Online Calculator

How It Works

Calculate how many gallons of paint you need to cover a room, wall, or exterior surface. Accounts for doors, windows, and number of coats required. Prevents over-buying or under-buying paint for any interior or exterior project

Note: Interpret the paint coverage result against the clinical thresholds and context described above.

How to Use

Enter the values for the patient or scenario you are assessing. Calculate how many gallons of paint you need to cover a room, wall, or exterior surface. Accounts for doors, windows, and number of coats required. Prevents over-buying or under-buying paint for any interior or exterior project. Use the paint coverage result to inform your clinical assessment.

Glossary and Definitions

Paint calculator: A key concept in Paint Coverage: Calculate how many gallons of paint you need to cover a room, wall, or exterior surface. Accounts for doors, windows, and number of coats required. Prevents over-buying or under-buying paint for any interior or exterior project.
Gallons of paint: A key concept in Paint Coverage: Calculate how many gallons of paint you need to cover a room, wall, or exterior surface. Accounts for doors, windows, and number of coats required. Prevents over-buying or under-buying paint for any interior or exterior project.
Wall coverage: A key concept in Paint Coverage: Calculate how many gallons of paint you need to cover a room, wall, or exterior surface. Accounts for doors, windows, and number of coats required. Prevents over-buying or under-buying paint for any interior or exterior project.
Room painting: A key concept in Paint Coverage: Calculate how many gallons of paint you need to cover a room, wall, or exterior surface. Accounts for doors, windows, and number of coats required. Prevents over-buying or under-buying paint for any interior or exterior project.
Paint estimator: A key concept in Paint Coverage: Calculate how many gallons of paint you need to cover a room, wall, or exterior surface. Accounts for doors, windows, and number of coats required. Prevents over-buying or under-buying paint for any interior or exterior project.
Paint Coverage: The Paint Coverage computes a result from the inputs you provide, based on the method described above.

Paint Coverage Calculator

Recipe Scaler

How It Works

How to Use

Glossary and Definitions

Frequently Asked Questions