Exterior Paint Calculator

Enter your house perimeter, wall height, window and door openings, and number of coats to calculate exactly how much exterior paint you need and what it will cost.

Created by Luis GonzalezLast updated: May 9, 2026

How to Use This Calculator

1
Enter House Perimeter
Measure the total perimeter of your home at the base in feet. Sum the length of all exterior walls.
2
Input Wall Height
Provide the average height of your exterior walls from the ground to the roofline. A typical single-story home is 9-10 ft, while a two-story is 18-20 ft.
3
Specify Openings Area
Enter the total square footage of all doors and windows combined. If unsure, estimate 15-20 sqft per standard opening.
4
Select Number of Coats
Choose the number of paint coats you plan to apply. Two coats are standard for durability; one for touch-ups or primer.
5
Define Coverage per Gallon
Input the paint's estimated coverage in square feet per gallon, typically 300-400 sqft/gal for exterior paints.
6
Enter Price per Gallon
Provide the average retail price per gallon for your chosen paint. Premium exterior paints typically cost $40-$70 per gallon.
7
Review Your Results
The calculator will display the estimated paint needed, total cost, and a breakdown of container requirements.

Example Calculation

A homeowner needs to paint a house with a 180 ft perimeter, 20 ft wall height, 120 sqft of openings, applying 2 coats of paint that covers 350 sqft/gal and costs $45/gal.

House Perimeter (ft)

180

Wall Height (ft)

Openings Area (sqft)

120

Number of Coats

Coverage per Gallon (sqft/gal)

350

Price per Gallon ($)

Results

20.0 gal

Tips

Account for Gables and Dormers

For more accurate results, calculate the area of triangular gables or complex dormers separately and add them to your total wall area before inputting.

Primer is Key

Always use a high-quality exterior primer, especially when painting new surfaces, changing colors dramatically, or covering stains. This improves adhesion and paint longevity.

Buy in 5-Gallon Buckets

If your project requires more than 5 gallons, buying 5-gallon buckets is typically more cost-effective per gallon and ensures better color consistency across the entire batch.

The Exterior Paint Calculator helps homeowners accurately estimate the gallons of paint, total cost, and container breakdown needed for an exterior house painting project. By considering factors like perimeter, wall height, openings, coats, and paint coverage, this tool provides a robust estimate. This is crucial for managing budgets and logistical planning, especially for projects in 2025 where paint and labor costs can vary significantly, ensuring you purchase precisely what's needed without waste or delays.

Why Strategic Planning for Exterior Home Painting Matters

Strategic planning for exterior home painting is a critical investment in your property's value and protection. A well-executed paint job not only enhances curb appeal, potentially adding 2-5% to your home's market value, but also provides a vital protective barrier against weather, UV radiation, and pests. Professional painting bids typically range from $2.50 to $6.00 per square foot, depending on location, surface preparation, and complexity. A quality exterior paint job, often lasting 7-10 years, offers a significant return on investment by deferring major maintenance and preserving structural integrity.

How to Estimate Paint Gallons and Project Costs

This calculator estimates the total paint needed by first determining the gross wall area (perimeter × height). It then subtracts the area of openings (doors and windows) to find the net paintable area. This net area is multiplied by the number of desired coats to get the total square footage that needs to be covered. Finally, this figure is divided by the paint's coverage rate per gallon to yield the total gallons required, which is then rounded up to the nearest whole gallon for purchasing. The total cost is derived by multiplying the rounded-up gallons by the price per gallon.

Gross Wall Area = House Perimeter × Wall Height
Net Paintable Area = Gross Wall Area - Openings Area
Total Sqft to Cover = Net Paintable Area × Number of Coats
Gallons Needed = Ceiling(Total Sqft to Cover / Coverage per Gallon)
Total Cost = Gallons Needed × Price per Gallon

💡 For other home renovation estimates, our Acrylic Paint Drying Time Estimator can help you plan project timelines more effectively.

Budgeting for a Two-Story Home Exterior Paint Job

Consider a homeowner with a two-story house: a perimeter of 180 ft, an average wall height of 20 ft, and 120 sqft of openings (doors/windows). They plan for two coats of paint, expect 350 sqft/gal coverage, and the paint costs $45/gal.

Calculate Gross Wall Area: 180 ft × 20 ft = 3,600 sqft
Calculate Net Wall Area: 3,600 sqft - 120 sqft = 3,480 sqft
Calculate Total Square Footage to Cover: 3,480 sqft × 2 coats = 6,960 sqft
Calculate Gallons Needed: 6,960 sqft / 350 sqft/gal = 19.88 gallons Rounded up for purchase: 20 gallons
Calculate Total Estimated Cost: 20 gallons × $45/gallon = $900
Result: The project will require 20.0 gallons of paint, costing an estimated $900.

💡 To plan for other improvements impacting home comfort, our Acoustic Insulation Calculator can help estimate materials for soundproofing.

Environmental & Safety Standards in Exterior Painting

Exterior painting projects are subject to various environmental and safety standards, particularly concerning lead-based paint and volatile organic compound (VOC) emissions. For homes built before 1978, the Environmental Protection Agency (EPA) mandates specific lead-safe work practices under its Lead Renovation, Repair, and Painting (RRP) Rule, requiring certified professionals for renovation activities that disturb lead paint. Many local building codes and Homeowners Association (HOA) regulations also dictate acceptable exterior paint colors and finishes to maintain neighborhood aesthetics. Furthermore, modern paint formulations increasingly adhere to VOC limits, aimed at reducing air pollution and improving indoor air quality, with many regions now promoting or requiring low-VOC or zero-VOC products in 2025.

Understanding Pricing Tiers for Exterior Paints

Exterior paint prices can range significantly, typically from $30 to over $70 per gallon, reflecting differences in quality, durability, and specialized features. Budget-friendly paints (e.g., $30-$40/gallon) often offer basic protection and coverage, suitable for quick refreshes or less exposed areas, but may require more coats or earlier repainting. Mid-range options ($40-$55/gallon) provide a good balance of performance, coverage (around 350-400 sqft/gal), and longevity, making them a popular choice for most homeowners. Premium-grade paints ($55-$70+/gallon) feature advanced formulations with enhanced adhesion, mildew resistance, and color retention, often lasting 10-15 years or more. These higher-tier paints are a worthwhile investment for challenging climates or demanding surfaces.

Frequently Asked Questions

How do I calculate the paintable area of my house exterior?

To calculate the paintable area, first find the gross wall area by multiplying the house perimeter by the average wall height. Then, subtract the total square footage of all windows and doors. For example, a house with a 180 ft perimeter and 20 ft wall height has a gross area of 3,600 sqft. If it has 120 sqft of openings, the net paintable area is 3,480 sqft. Don't forget to account for any gables or unique architectural features.

What is a good coverage rate for exterior paint?

A good coverage rate for exterior paint typically ranges from 300 to 400 square feet per gallon per coat. Premium paints often offer better coverage, while rough or porous surfaces like stucco or unprimed wood will significantly reduce this rate, sometimes to as low as 200 sqft/gal. Always check the specific paint can label for its recommended coverage, as this directly impacts how many gallons you'll need for your project.

How much does it cost to paint a house exterior per square foot?

The cost to paint a house exterior can vary widely, but typically ranges from $2.50 to $6.00 per square foot for professional services. This cost includes both labor and materials. Factors influencing this rate include the number of stories, surface preparation required, paint quality, and regional labor rates. DIY projects, while saving on labor, still incur material costs, which for a quality exterior paint might be $0.10-$0.20 per square foot in 2025.

Is it cheaper to buy exterior paint in 1-gallon or 5-gallon containers?

It is almost always cheaper to buy exterior paint in 5-gallon buckets compared to individual 1-gallon cans, assuming you need more than a few gallons. Retailers typically offer a bulk discount on larger containers, which can save you 10-20% per gallon. Additionally, purchasing from a single large batch minimizes the risk of slight color variations between cans, ensuring a more uniform finish across your entire home exterior.