Roof materials
Ridge vent length calculator
Estimate ridge-vent stock pieces. A measured ridge uses a selected vent stock length.
Try the calculation
Count stock pieces for a measured ridge run. Ventilation sizing is not calculated here.
Adjustable example. Change these illustrative inputs to match your task, then recalculate. Reset restores the example and its result.
Understand the result
How this calculation works
Ridge vent length is stock-piece rounding for a measured ridge run.
Steps
- Enter ridge length and the selected vent-piece length.
- Use one product length at a time.
The form starts with the worked example below. Change its values and selections to match your task; Reset restores the example.
Formula
pieces = ceiling(ridge length ÷ piece length).
Variables and units
- Ridge length (ft)
- Required. Use a positive value. Starting example: 120. Replace it for your task.
- Vent-piece length (ft)
- Required. Use a positive value. Starting example: 4. Replace it for your task.
What the result means
It counts vent pieces only. It does not size NFVA or decide whether a ridge vent is appropriate.
Worked example
Inputs: Ridge length = 120; Vent-piece length = 4.
Calculation: 120 ft ÷ 4 ft per piece = 30 pieces.
Result: 30 pieces.
Frequently asked questions
Can I use this for hip venting?
Only if the selected product and measured run support that use.
Does it include end caps?
No, accessories are separate.
Why not use attic area?
Vent length is a stock takeoff; use the ventilation page for NFVA.