How many soffit stock panels do you need?
Measure the total eave run and the uniform projection to be covered. Enter the usable installed width and stock length of the selected panel. The worksheet calculates strip count, cuts per stock length and a whole stock-panel purchase with optional spare allowance.
Which panel width should be entered?
Use installed coverage width rather than total width including concealed overlap or interlock. Eave run is divided by that usable width to count the strips. The strips extend across the soffit projection, while their coverage width advances along the eave.
How do cut depth and saw kerf affect stock yield?
Cuts per stock = floor((stock length + kerf)/(cut depth + kerf)). The final piece does not need a following kerf, which is why the stock numerator includes one kerf. If no cut fits, the worksheet rejects the stock selection. This model assumes equal-depth straight cuts.
Panel strips = ceil(eave run ÷ usable panel width); cuts per stock = floor((stock + kerf)/(cut depth + kerf)); intake NFVA = attic area/ratio × required intake share
What does a forty-foot eave example need?
With 40 ft run, 2 ft projection and 12 in installed panel width, 40 strips cover the eave. A 12 ft stock panel yields six strips when kerf is zero. Forty divided by six rounds up to seven stock panels, leaving two spare strips before an additional allowance.
How should trim and channel stock be counted?
Enter the separately measured total trim length and stock length together for an aggregate length minimum. That count does not optimize individual mitered cuts or reuse offcuts. Front and back channels, returns and corners can have different lengths, so derive the total from the actual installation details.
What is the difference between perforated area and NFVA?
Net free ventilation area describes effective product openings, not gross soffit face area. The optional check requires the product NFVA per linear foot or per linear meter. It converts the selected product basis before comparing the installed ventilated run with the required intake area.
How is the specified intake target calculated?
Required total ventilation area is attic floor area divided by the project denominator. Multiply by the specified intake share to get the intake target, then divide by product NFVA per run length. Enter the applicable project values rather than assuming a ratio or intake split; exhaust balance, obstructions and installation details remain separate checks.
Which input units and assumptions should you check?
Use the labeled units and measured project values. Optional fields remain blank unless their data are available; paired fields must be entered together. Straight-run takeoff with no mixed-depth offcut reuse. Enter the applicable ventilation ratio, intake allocation and product net free area; this is not a code approval.
| Input | Unit basis | When used |
|---|---|---|
| Total eave run | ft / m | all modes |
| Soffit projection / panel cut depth | ft / m | all modes |
| Usable installed panel width | in / cm | all modes |
| Panel stock length | ft / m | all modes |
| Cut kerf (optional) | in / cm | all modes |
| Spare panels (%) (optional) | as labeled | all modes |
| Price per stock panel (optional) | as labeled | all modes |
| Measured channel / trim total (optional) | ft / m | all modes |
| Trim stock length (optional) | ft / m | all modes |
| Attic floor area | ft² / m² | vent:yes |
| Project total vent area denominator | as labeled | vent:yes |
| Required intake share (%) | as labeled | vent:yes |
| Product intake NFVA per selected run unit | as labeled | vent:yes |
| Installed ventilated run (optional) | ft / m | vent:yes |
How can you compare and save different scenarios?
Calculate and save a baseline to comparison, change one input and calculate again. Review the itemized results before transferring values. Copy or share the result, download the input and result sheet, or print the worksheet. Clear changes removes the current inputs and results, and refresh starts clean.
Which related calculators help with the next step?
Use Roofing Calculator and Roof Pitch Calculator. Check that the measurement units and scope match before using a result as an input elsewhere.
