Room Area Calculator
Calculate floor, ceiling, gross wall, net wall, and selected finish areas.
What this calculator does
Wall perimeter is multiplied by height before openings are deducted.
Room surfaces
Enter combined opening face areas. Every room surface is shown separately for reuse.
Your plan updates instantly
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Perimeter x height gives gross walls; openings are deducted.
The arithmetic uses the exact values shown above. Verify field measurements, product pack sizes, layout constraints, and local requirements before ordering or building.
How to interpret the result
Wall perimeter is multiplied by height before openings are deducted.
How the result is calculated
Net walls = 2 x (length + width) x height - openings.
Worked example
A 14 x 12 x 8 ft room has 416 ft² of gross walls.
Practical guidance
- Measure the project at least twice before ordering.
- Use actual product dimensions and package coverage.
- Keep a saved or printed copy of the inputs used for the estimate.
Assumptions and limitations
A rectangular room with level ceiling is assumed; recesses and sloped surfaces are separate.
Methodology
Calculations use standard geometry and normalized units. Countable products are rounded up where partial products cannot normally be purchased.
Read the complete calculation methodology and testing policy.
Frequently asked questions
Are results rounded for purchasing?
Countable materials and packages are rounded up. Measured area, length, volume, and cost remain decimal values where appropriate.
Is this a final construction specification?
No. It is a transparent planning estimate. Verify product instructions, site conditions, plans, and local requirements.