Wall
Calculate wall area from width and height, then subtract windows and other openings row by row.
Paintable Surface Area Calculator (Walls, Roofs, Tanks, Pipes, Steel Sections, Fences)
Calculate wall, roof, tank, pipe, steel-section, fence, and direct-input areas in one tool. Pass the net area directly to the Paint Quantity Calculator.
Roof pitch and cylindrical surfaces in one tool
Supports opening deductions, end caps, and editable factors
Built for international teams and projects
Inputs stay in this browser and are never sent to a server.
How to use
- Select a unit system and add one row per surface type.
- For walls, add openings to deduct windows and doors. For roofs, choose a pitch method.
- For tanks, pipes, steel sections, and fences, enter the dimensions, quantity, and required factor or profile.
- Review the net area, then pass it to the Paint Quantity Calculator for coating volume.
Supported shapes
Roof
Convert angle, rise/run, or percent pitch into a slope factor and apply it to the plan area.
Tank
Switch between vertical and horizontal tanks and include end caps when required by the specification.
Pipe
Calculate outside surface area from diameter and length; add end faces only when needed.
Steel sections
Choose a preset section or enter a custom perimeter for a quick coating takeoff.
Fence
Estimate one-sided, two-sided, or open-mesh fencing with an editable factor.
Direct input
Enter an area directly when the drawing or takeoff already gives you the value.
Sample
Input
Wall with window deduction
Wall 6.0 m × 3.0 m, window 1.0 m × 1.5 m × 1
Output
Gross 18.00 m² / Deduction 1.50 m² / Net 16.50 m²
Input
Roof pitch area
Roof 5.0 m × 4.0 m, pitch 45°, quantity 1
Output
Multiply the plan area by the pitch factor to get 28.28 m² net area
Formulas
- Wall: Gross area = width × height × quantity
- Opening deduction: Deduction area = Σ(opening width × opening height × quantity)
- Roof: Net area = plan area × slope factor × quantity
- Tank / pipe: Area = π × diameter × length × quantity
- Steel section: Area = perimeter × length × quantity
- Fence: Area = length × height × factor × quantity
Glossary
Gross area
The area before deductions are removed. For walls, it starts with width × height; for roofs, it starts with plan area × slope factor.
Deduction area
The area removed for windows, openings, cutouts, or similar voids.
Net area
The area that will actually be painted. This is the value you pass to the paint quantity calculator.
Slope factor
The multiplier that converts plan area into sloped roof area.
Factor
A multiplier used to approximate open fencing, double-sided coating, and similar cases.
Important notes
- This result is an estimate. Use on-site measurements and the drawing set as the final reference.
- Preset steel perimeters are approximate. Enter a custom perimeter when you need more precision.
- Tank end caps, pipe end faces, and fence factors can vary by specification.
- After calculating the net area, continue in the Paint Quantity Calculator for coating volume and dilution.
FAQ
Which roof-pitch method should I use?
Use the method shown on the drawing or site note—angle, rise/run, or percent. Each method is converted to the same slope factor.
How accurate are the preset steel-section areas?
Presets are for quick estimates. Enter a custom perimeter when you need greater accuracy.
Can I enter multiple window deductions on one wall?
Yes. Add multiple opening rows and enter each width, height, and quantity separately.
Can a shared URL restore the same setup?
Yes. A shared URL can restore the row structure, unit system, and display settings.
How do I continue in the Paint Quantity Calculator?
Select the handoff button to carry the net area into the Paint Quantity Calculator.