Paint coverage calculator.
Type in your room perimeters and heights. Get paintable square footage, gallons of paint by coat, primer, tape, rollers, brushes and caulk — and download it as a proper Excel takeoff with live formulas.
| Room / area | Wall perimeter (ft) | Height (ft) | Openings SF | Ceiling SF (opt.) | Paintable SF |
|---|
| Material | Qty | Unit | How it’s figured |
|---|
How the math works
Every factor in this calculator is a standard painting rule of thumb, and every one of them is visible in the Excel download so you can audit or adjust it:
- Paintable SF — (wall perimeter × ceiling height − openings SF) + optional ceiling SF, per room.
- Paint gallons — paintable SF × coats × (1 + waste) ÷ coverage (350 SF/gal default), rounded up to whole gallons.
- Primer gallons — paintable SF ÷ primer coverage (300 SF/gal default), one coat, rounded up — only when primer is on.
- Painter’s tape — one roll per 400 SF of paintable area.
- Roller covers — one per 500 SF of paintable area.
- Brushes — a flat 2 per job for cutting in.
- Drop cloths — one per 300 SF of paintable area.
- Caulk — one tube per 40 LF of perimeter (trim, gaps and corners).
This is the easy 20%. The other 80% is on your drawings.
A coverage calculator prices the rooms you already understand. What it can’t do is read a finish set: the room finish schedule, the accent walls, the substrate-specific coat counts, the high-build epoxy in the back of house, the ceiling-vs-wall sheen split. That’s the part of a paint bid that leaks money — and it’s exactly what Pilars AI takeoff for painting does from your actual plans: it reads the finish schedule, classifies every surface, and returns gallons, primer and sundries by product. $100 per trade, per plan.
Questions painters actually ask
How does the calculator figure paintable square footage?
For each room: wall perimeter × ceiling height, minus the door and window SF you enter, plus any optional ceiling SF. That paintable area drives every quantity.
How many gallons of paint will I need?
Paintable SF × coats × (1 + waste) ÷ coverage per gallon (350 SF default), rounded up to whole gallons. Match the coverage rate to your product data sheet and it recalculates.
Does it include primer?
Yes when you turn primer on — one coat at its own coverage rate (300 SF/gal default, since primer covers less than topcoat), rounded up to whole gallons.
Can I download the takeoff as Excel?
Yes — one click exports a real .xlsx workbook with a Rooms sheet and a Materials sheet. The cells carry live Excel formulas, so you can change perimeters, coats, coverage or waste inside Excel and everything recalculates. There’s a blank reusable template too.
Is this as accurate as a real plan takeoff?
It’s a fast estimating tool built on standard coverage rates. It doesn’t read your finish schedule, accent walls or substrate-specific coats — that’s what Pilars does from your actual drawings for $100 per trade.
Let Pilars take off your whole set.
Upload your plans. Pilars reads the finish schedule, separates wall and ceiling sheens, catches accent walls and high-build coatings, and returns the full painting takeoff — gallons, primer and sundries. $100 per trade.