Paint & Primer Coverage with Waste Calculator

Plan your painting project with precise room math coverage adjustments and waste sliders Get quantities for primer and paint choose the cheapest can combination see costs generate a clean printable estimate export CSV and work faster in imperial or metric for contractors DIYers and facility managers with friendly intuitive controls helpful defaults and validation

Project & Units

Affects baseline waste.

Surface & Coats

Factor applied to coverage (lower = more product).

Coverage (per gallon or per liter)

ft²/gal (typical)
ft²/gal (typical)

Rooms & Areas

Room L W H Doors Windows Openings Area Ceiling?
ft
in
Used to compute trim area.

Waste & Contingency

Primer Waste 8%

Includes cut-in, roller residue, spills, absorption, and method loss.

Paint Waste 10%

Adjust based on skill level and complexity; spray typically higher.

Can Sizes & Prices

Primer Pricing

Leave blank to assume linear pricing from per-gallon.

Paint Pricing

Enter your store prices to optimize cost.

Summary

Imperial

0 ft²

Total Paintable Area
Walls/Ceilings/Trim
  • Primer (pre-waste) 0 gal
  • Primer (purchase) 0 gal
  • Paint (pre-waste) 0 gal
  • Paint (purchase) 0 gal

Optimized Can Mix

Min cost, then least leftover.

Cost Estimate

Primer$0
Paint$0
Total$0
Assumptions & Tips
  • Coverage is can-label typical and adjusted for porosity.
  • Waste sliders include cut-in, residue, spills, and method loss.
  • Openings: doors≈21 ft², windows≈12 ft² (edit in table).
  • Use Print / Save PDF for a client-ready estimate.

Pre-waste quantity = Area × Coats ÷ (Coverage × PorosityFactor). Purchase quantity divides by (1 − Waste%). Can optimization then finds the lowest cost combination that meets or slightly exceeds the purchase quantity.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.