Why is the floor excluded by default?
Paint and putty work is almost never applied to the floor — floors are tiled or polished separately. Toggle it on if you need the floor area included (e.g., for floor coatings or epoxy work).
calculators tool
Room Surface Area Calculator
Calculate paintable wall area for any room — deduct doors, windows, and AC openings; exclude skirting; add lofts or projections. Download a detailed PDF report. Useful for painting, putty, and civil work estimates.
Room details
Surfaces
Front Wall12×10 ft120.00 sq ft
Skirting
Back Wall12×10 ft120.00 sq ft
Skirting
Left Wall10×10 ft100.00 sq ft
Skirting
Right Wall10×10 ft100.00 sq ft
Skirting
Common items
Items not tied to a specific wall — e.g. a large skylight, a circular cutout, or any area that spans multiple surfaces.
Net Paintable Area
560.00 sq ft
Room 1 · 12×10×10 ft
Surface breakdown
- Front Wall(12 × 10 ft)
- 120.00 sq ft
- Back Wall(12 × 10 ft)
- 120.00 sq ft
- Left Wall(10 × 10 ft)
- 100.00 sq ft
- Right Wall(10 × 10 ft)
- 100.00 sq ft
- Ceiling(12 × 10 ft)
- 120.00 sq ft
- Floor(12 × 10 ft)
- —
About This Tool
When getting a painting or putty quote, the painter charges by square foot. Knowing the exact net paintable area prevents overcharging and helps you compare estimates fairly.
This tool starts with your room's four walls, ceiling, and floor, then lets you deduct doors, windows, AC openings, skirting bands, and even skip entire walls. You can also add extra surfaces like open lofts or projections.
Tapered walls (sloped ceiling, like in an attic room or under a staircase) are supported — just toggle the tapered option on a wall and enter the height at both ends. Circular and triangular deductions (arched windows, arch openings) are also handled.
Download a structured PDF report you can share with your contractor or keep for your records.
How To Use
- 1. Enter the room name and dimensions — Length, Breadth, and Height in feet.
- 2. In the Surfaces section, toggle off any walls you want to exclude. For walls with sloped ceilings, enable Tapered and enter the height at the far end.
- 3. Toggle Ceiling and Floor on or off as needed. Enter a Skirting height in inches (e.g. 6 in) if a skirting band should be excluded from the wall area.
- 4. Under Deductions, click Add Deduction and choose Door, Window, AC, or Custom. Set dimensions and count. For circular openings like round windows, switch the shape to Circle and enter the diameter.
- 5. Under Additions, click Add Area for any extra surfaces — open loft above the room, a projecting beam face, or any area to be added back.
- 6. The Results panel updates live. Click Download PDF Report to save a detailed breakdown.
Frequently Asked Questions
What is skirting height and when should I use it?
Skirting is the bottom strip of the wall that usually gets tiles, wood panelling, or a skirting board instead of paint. If your room has a 6-inch tile skirting along the base of each wall, enter 6 in the skirting height field and that strip will be deducted from all included walls automatically.
How do I handle a wall with a sloped ceiling (tapered wall)?
Expand the wall card and enable Tapered. Enter the room height at the near end and the height at the far end. The area is calculated as a trapezoid: (H1 + H2) / 2 × Width.
Can I deduct a circular window or arch opening?
Yes — when adding a deduction, switch the shape chip from Rect to Circle and enter the diameter. The tool calculates π × (diameter/2)² for the area.
What does the PDF report include?
The PDF contains the room name and dimensions, a per-surface breakdown table, a deductions table, an additions table, and a summary box showing gross area, skirting deduction, net deductions, net additions, and the final net paintable area.