Coverage calculator
How much paint do I need?
Estimate paint needs using dimensions, hull type, coat count, and waste allowance. This gives a more flexible planning model than a static boat-size lookup table.
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How the Boat Paint Calculator Works
Our paint calculator uses a multi-factor formula that accounts for your boat's length, beam width, and freeboard height to estimate total paintable surface area. Unlike simple lookup tables that only use overall boat length, our calculator adjusts for hull type — a catamaran has significantly more surface area than a runabout of the same length, and a sailboat's deep keel adds area that a flat-bottomed hull does not have.
The waste factor accounts for paint lost to rollers, brushes, drips, touch-ups, and overspray. First-time painters should use a higher waste factor (15-20%) while experienced applicators can use 8-12%. Two coats is the industry standard for marine topcoats — it ensures full opacity, even color, and a proper protective film build that will hold up to UV exposure and saltwater immersion.
The recommended product is automatically selected based on your surface type. The calculator then divides your total adjusted area by the product's coverage rate (square feet per gallon) to give you a reliable gallon count and cost estimate.
Tips for Accurate Estimates
- Measure at the waterline, not overall length. Your boat's LOA (length overall) includes bowsprits, swim platforms, and other overhangs that are not painted surfaces. Use waterline length for the most accurate estimate.
- First-time painters should add 15-20% waste. Paint gets lost to roller covers, brush loading, drips, and touch-ups. Experienced painters can use 10-12%, but it is always better to have extra paint than to run short mid-project.
- Rough or porous surfaces need more paint. Bare wood, etched fiberglass, and textured concrete absorb more paint than smooth, previously painted surfaces. Expect 15-25% higher consumption on unsealed surfaces.
- Always apply a minimum of 2 coats. One coat rarely provides full opacity or adequate film build for marine durability. Two coats is the professional standard. Three coats is recommended for dark colors and high-UV environments.
- Leading edges need an extra coat. The bow, waterline edge, rub rail, and any area that takes direct wave impact should get one extra coat or a heavier application for added protection.