Exterior Paint Calculator
Calculate exterior paint requirements for siding, trim, doors, and shutters. Accounts for surface texture, number of coats, and primer needs.
Exterior Paint Calculator
Calculate exactly how much paint and primer you need
Project Details
Non-porous, smooth surface. Best coverage rates.
Always required for bare wood, masonry, and metal. Can be skipped on previously painted surfaces in good condition with same/darker colors.
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"Calculate Paint Needed" to see results
Based on professional industry standards from PCA (Painting Contractors Association) and MPI (Master Painters Institute). Calculations account for surface porosity, texture, and application method.
Frequently Asked Questions
How much does exterior paint cover per gallon?
Smooth siding covers 350-400 square feet per gallon. Textured surfaces cover 250-300 square feet per gallon. Rough stucco or porous brick covers 200-300 square feet per gallon. Coverage depends on surface texture, porosity, and application method.
How much does primer cover per gallon?
Primers universally cover less than topcoats, standardizing at 200-300 square feet per gallon across all manufacturers regardless of surface type. This reduced coverage accounts for better penetration and surface sealing.
How many coats of exterior paint do I need?
Most exterior projects require 2 coats. Previously painted surfaces in good condition may need only 1 coat if using high-quality paint and similar colors. Bare wood, new siding, or dramatic color changes require 1 primer coat plus 2 finish coats.
Should I paint trim and siding separately?
Yes, calculate trim separately. Trim, fascia, and soffits use different paint types (often semi-gloss vs satin for siding). Trim typically requires 1-2 quarts per 500 square feet of siding. Doors and shutters are calculated individually as accent areas.
Industry Standards Referenced
ASTM D3276 - Standard Guide for Painting Inspectors(ASTM D3276-15)
View StandardComprehensive guide for exterior paint inspection covering surface preparation, application methods, film thickness, and quality control for masonry, wood, and metal substrates.
Key Requirements:
- •Surface prep: Clean, dry, and stable before painting (moisture ≤15%)
- •Primer required: New wood, repairs, masonry, or substrate changes
- •Film thickness: 4-6 mils wet, 1.5-2.5 mils dry per coat minimum
- •Adhesion testing: Cross-hatch or pull-off test for quality assurance
- •Temperature: Apply when surface temp is 50-90°F, no rain within 24 hours
Vinyl Siding Institute (VSI) Paint Guidelines(VSI Standards)
View StandardGuidelines for painting vinyl siding to prevent heat warping. Requires specific Light Reflectance Value (LRV) ratings to avoid vinyl distortion from heat absorption.
Key Requirements:
- •LRV rating: Minimum 55 or higher (lighter colors only)
- •Dark colors prohibited: Can cause vinyl to warp from heat (up to 160°F surface temp)
- •Surface cleaning: TSP wash, rinse thoroughly, allow to dry
- •Paint type: 100% acrylic latex designed for vinyl and plastic
- •Warranty: Painting may void vinyl manufacturer warranty - verify first
PDCA - Painting & Decorating Contractors of America Standards(PDCA P1-P20)
View StandardProfessional painting standards for residential and commercial exteriors. Covers surface preparation levels, application methods, coating specifications, and quality benchmarks.
Key Requirements:
- •Surface prep levels: P1 (minimal) to P5 (maximum) based on condition
- •Two-coat minimum: Primer + finish or two finish coats
- •Drying time: 24 hours between coats at 70°F, longer in cold/humid weather
- •Application method: Brush, roll, or spray based on substrate and texture
- •Spot priming: All repairs, stains, and substrate changes before topcoat
National Roofing Contractors Association (NRCA) - Fascia/Soffit(NRCA Guidelines)
View StandardStandards for painting fascia, soffits, and trim boards that interface with roofing systems. Emphasizes moisture barriers and proper priming to prevent wood rot.
Key Requirements:
- •Prime all six sides: Prevents moisture intrusion from behind
- •Aluminum coil stock alternative: Consider pre-finished metal trim
- •Ventilation: Don't paint over soffit vents (blocks airflow)
- •Back-side sealing: Critical for fascia exposed to roof runoff
EPA Lead-Safe Renovation Rule (RRP)(40 CFR 745)
View StandardFederal requirements for disturbing lead paint in homes built before 1978. Contractors must be EPA-certified and follow lead-safe work practices when scraping, sanding, or removing old paint.
Key Requirements:
- •Pre-1978 homes: Assume lead paint present until tested
- •Certified renovators: EPA RRP certification required for contractors
- •Containment: Plastic sheeting, warning signs, restrict access
- •Cleanup: HEPA vacuum, wet cleaning, proper waste disposal
- •Documentation: Provide lead pamphlet, keep records 3 years
Standards Disclaimer: Standards and codes are subject to periodic updates. Always verify current requirements with local building authorities and professional engineers before beginning construction. Links provided are for reference only.
Want to Learn More?
Coverage rates for siding, trim, and doors with PDCA standards and surface preparation requirements.
Read the Exterior Paint Coverage GuideHow to Use This Calculator
- Measure surfaces: Enter square footage for siding, trim, and other areas.
- Select surface texture: Smooth surfaces use less paint than rough.
- Choose coating system: Primer + 2 coats recommended for bare wood.
- Review gallons needed: See separate amounts for primer and finish coats.
Exterior Paint Coverage Standards
Smooth siding: 350-400 sq ft/gal. Rough wood: 250-300 sq ft/gal. Stucco: 150-200 sq ft/gal. Always prime bare wood and metal.