Siding Calculator
Measure exterior wall sections, subtract openings, add a transparent waste allowance and calculate whole siding packages or squares from the product coverage.
Enter measured wall sections and the usable coverage from your product label. A square is commonly 100 ft², but this tool uses your entered coverage.
Wall section 1
Siding estimate
Main wall
- Net area
- 26 m²
- Required with waste
- 28.6 m²
- Packages
- 3
- Purchase coverage
- 30 m²
Labor, trim, flashing, starter strips, tax, delivery and installation are excluded. Use measured quantities and installer guidance.
Next, see the design direction
Try it in your own room
Review your brief, then take it into Roomagic Studio. AI previews require login and use your existing credits. Nothing is generated automatically.
How siding quantity is calculated
Net wall area is the sum of measured wall rectangles minus doors, windows and other uncovered openings. Required coverage = net area × (1 + waste allowance). Packages are rounded up using the usable coverage printed on your product label.
Measure walls and openings separately
Split gables, additions and other sections into measured rectangles. Do not subtract an opening twice, and keep trim, soffits and different siding products as separate groups.
What this estimate does not verify
The calculator does not infer wall area from a photo, model roof pitch, optimize cuts, verify starter strips or flashing, or replace a takeoff by a qualified installer. Follow the manufacturer and local requirements.
Frequently asked questions
What is a siding square?
A siding square is commonly 100 square feet of coverage, but product packaging and usable coverage vary. Enter the coverage shown for the product you plan to buy.
Can I estimate different siding products?
Yes. Add a separate product group for each siding type or color so each has its own coverage, waste and price.
Does this include trim and flashing?
No. Add those as separate measured line items in the remodel cost calculator or follow the installer’s takeoff.
Method and rule notes
Roomagic’s editorial style profiles use the scoring method described above. Suggestions are subjective and can be changed.
Rule notes reviewed October 21, 2026.