Pergola Material Calculator
Estimate preliminary pergola post, beam, rafter and shade-slat quantities, total lumber length and material cost for a rectangular layout.
Default project preview
6 posts
Side beams
4
Rafters
9
Shade slats
13
Post positions per side
3
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Pergola length
Enter this project assumption in ft. The current imperial default is 16 ft.
Pergola width
Enter this project assumption in ft. The current imperial default is 12 ft.
Maximum post spacing
Enter this project assumption in ft. The current imperial default is 8 ft.
Rafter spacing
Enter this project assumption in in. The current imperial default is 24 in.
Shade-slat spacing
Enter this project assumption in in. The current imperial default is 12 in.
Stock post length
Enter this project assumption in ft. The current imperial default is 10 ft.
Price per post
Enter this project assumption in a unitless value. The current imperial default is 30. Minimum: 0.
Price per side-beam piece
Enter this project assumption in a unitless value. The current imperial default is 45. Minimum: 0.
Price per rafter
Enter this project assumption in a unitless value. The current imperial default is 18. Minimum: 0.
Price per shade slat
Enter this project assumption in a unitless value. The current imperial default is 8. Minimum: 0.
How to read the outputs
Side beams
two layers on two sides. Default preview: 4.
Rafters
entered spacing. Default preview: 9.
Shade slats
entered spacing. Default preview: 13.
Post positions per side
including both ends. Default preview: 3.
Total lumber length
nominal member lengths. Default preview: 440 ft.
Material cost
entered piece prices. Default preview: $626.00.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Post positions and horizontal members are rounded up from the entered spacings. Total lumber length sums posts, four side beams, rafters and shade slats.
Reviewed project guidance
How to use this estimate in a real project
Last reviewed: August 19, 2026
Estimate a preliminary pergola material takeoff from footprint, post count, beams, rafters and selected member spacing.
Calculation steps
- 1Define the pergola footprint and orientation.
- 2Enter the designed post/beam arrangement and rafter spacing.
- 3Calculate each member family separately by count and length.
- 4Convert member lengths to available stock only after overhangs, splices and connection details are known.
Worked numerical example
For a 12 ft × 16 ft pergola with rafters spaced 24 in on center across the 12 ft direction, roughly seven rafter lines span the 16 ft length before overhangs; posts and beams are counted from the chosen framing layout separately.
Purchasing and rounding
Create separate stock lists for posts, beams, rafters and slats because their sizes and lengths differ. Structural member sizes and connector requirements must come from the design, not from a generic quantity allowance.
Interpret the result
The result is a preliminary material takeoff for the geometry entered. It does not size members for wind, snow or seismic loads and does not determine footing or connection requirements.
Page-specific assumptions
- Member sizes and structural layout are already selected by an appropriate design process.
- Spacing is uniform within each member family.
- Decorative slats or roofing are calculated separately if not included.
Common mistakes
- Using footprint area as a substitute for member lengths.
- Applying rafter spacing in the wrong direction.
- Forgetting overhangs.
- Treating quantity output as structural sizing.
Primary and technical references
BuildMeter provides planning estimates, not engineering, architectural, electrical, mechanical, plumbing, permit or code approval. Review the methodology and verify final decisions with product documentation and qualified professionals.
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
Pergola Material Calculator questions
Why are four side beams included?+
The default model uses a double beam along each long side.
Does this choose lumber sizes?+
No. Member dimensions depend on span, species, loads and connection design.
Are footings included?+
No. Foundation quantities should be estimated separately after the footing design is established.