How to Estimate Paint Coverage from a Blueprint
The Paint Coverage Calculator estimates how much paint is required for walls or ceilings using blueprint measurements. Trace the surface area from a plan and calculate paint requirements based on standard coverage rates.
Upload your blueprint or plan image, set the scale from the title block or by calibrating from a known dimension, and trace each wall or ceiling area with the polygon or rectangle tool. The app computes total square footage and divides by your chosen coverage rate (e.g., 350 sq ft per gallon for standard latex) to estimate gallons. Add the number of coats and a waste factor for your final order quantity.
Scale calibration ensures accurate measurements. If your plan shows a dimension like "20 ft" on a wall, use the calibrate tool to draw a line over that dimension and enter 20 feet. The calculator then converts all traced areas to real-world square footage.
Standard Paint Coverage Rates
Coverage rates vary by paint type and surface texture. Most product labels specify coverage in square feet per gallon under ideal conditions. Standard latex and flat finishes typically cover 350–400 sq ft per gallon on smooth surfaces. Eggshell and satin fall in the same range.
Semi-gloss and gloss paints often cover slightly less due to higher solids. Primer and textured paints can vary widely. Always check your product label and factor in surface porosity and prep quality.
| Paint Type | Coverage per Gallon |
|---|---|
| Standard latex / flat | 350–400 sq ft |
| Eggshell / satin | 350–400 sq ft |
| Semi-gloss / gloss | 300–350 sq ft |
| Primer | 250–350 sq ft |
| Textured paint | 150–200 sq ft |
Number of Coats and Waste Factor
Most interior and exterior projects require two coats for even coverage and durability. Dark colors, dramatic color changes, or low-quality paint may need three. Multiply the gallons for one coat by the number of coats to get total paint needed.
A typical 10% waste factor accounts for spills, cut-in edges, touch-ups, and uneven application. Complex trim, textured surfaces, or inexperienced applicators may warrant 15% or more. Round up to whole gallons when ordering.
Frequently Asked Questions
How do I calculate how much paint I need from a blueprint?
Upload your blueprint, set the scale, trace the wall or ceiling area with the polygon or rectangle tool. Enter the coverage rate (e.g., 350 sq ft/gal) and number of coats. The calculator divides total area by coverage rate and multiplies by coats to get gallons. Add a waste factor for your order quantity.
What is the standard paint coverage rate per gallon?
Standard latex and flat paint typically cover 350–400 sq ft per gallon. Eggshell and satin are similar. Semi-gloss and gloss cover 300–350. Primer and textured paint may cover less. Check the product label for exact coverage.
How do I account for multiple coats of paint?
Multiply the gallons needed for one coat by the number of coats. The calculator does this automatically when you select 2 or 3 coats. For example, 400 sq ft at 350 sq ft/gal needs ~1.14 gal per coat; 2 coats = ~2.3 gal.
Should I add waste factor for paint estimation?
Yes. A 10% waste factor is typical for painting projects to account for spills, touch-ups, cut-in edges, and uneven coverage. Complex surfaces or textured walls may need more.
Can I use this calculator for exterior and interior painting?
Yes. The calculator works for any wall or ceiling surface. Use interior or exterior coverage rates from your paint product. Exterior paints often have similar coverage; textured surfaces may require different rates per gallon.