Model Paint Coverage Calculator

This calculator works backward from your model's surface area to a bottle count, so you buy exactly enough paint and not three bottles you'll never finish. It starts from your surface coverage rate (how many square inches one milliliter of paint covers when brushed or airbrushed thin) and multiplies by your number of coats to get total paint volume needed. Bare plastic or resin soaks up noticeably more paint than a primered surface before it looks opaque and even, so if you mark the surface as unprimed, the calculator adds a flat 20% to the area before converting to volume — a rule of thumb from hobby painting practice, not a physical law, so use it as a first approximation rather than an exact figure for every paint brand. The result is converted to both milliliters and fluid ounces, then divided by 17ml (the volume of a standard hobby paint dropper bottle, roughly 0.5oz) and rounded up to the next whole bottle, matching how the paint is actually packaged and sold.

If you didn't mark the surface as primered, it also estimates a separate primer volume — one coat's worth of area at a 10% coverage penalty versus your paint's own rate, reflecting that primer is usually laid down thicker for adhesion and tooth. Estimated cost assumes a flat $4 per bottle, which is a reasonable placeholder for craft-store acrylics but will run higher for specialty enamels or lacquers — swap in your own price per bottle for a real budget. Coverage rates vary a lot by paint brand, thinning ratio, and application method (airbrush vs. brush), so measure your own paint's actual coverage on scrap material if precision matters.