About this tool
The soffit and fascia calculator estimates how much material to order for finishing roof eaves. Enter the linear footage of eaves around your home and the soffit overhang width to get square footage, fascia trim, and fastener counts.
How it works
Fascia LF = Eaves LF
Screws = (Fascia LF × 3) + (Soffit ft² × 1)
Soffit area equals eave length multiplied by the overhang width converted to feet. Fascia matches the eave linear footage. Add a waste factor of 10 to 15 percent for cutting and overlaps.
How to use the Soffit and Fascia Calculator
The Soffit and Fascia Calculator is a browser-based tool that runs entirely on your device. Inputs you enter never reach a server - all calculations happen client-side in JavaScript. This means:
- Privacy: nothing is logged, sent, or stored by 3Tej. Inputs disappear when you close the tab.
- Speed: results update as you type. No network round trip.
- Offline use: once the page is cached, it works without internet.
- No signup: no account, no email, no rate limits.
Step by step
- Enter your inputs in the form above. Each field is labeled with its unit (currency, percent, kg, etc.) and the expected range.
- Read the result as it updates. The number reflects the formula commonly accepted in Soffit and Fascia-related calculations.
- Adjust to see sensitivity: change one input at a time and watch how the output moves. This is the fastest way to understand which variable matters most.
- Copy or screenshot the result for later reference. The page state persists for the session if your browser allows it.
When you would use this
- Quick estimates: when you need a number now and don't want to open a spreadsheet.
- Sensitivity analysis: testing how a result changes as inputs vary, before committing to a real-world decision.
- Comparison: running the same calculation with different inputs to compare options side by side.
- Learning: building intuition for how the underlying math behaves.
- Documentation: capturing a snapshot of inputs and outputs at a point in time.
Frequently asked questions
What is the difference between soffit and fascia?
Soffit is the horizontal underside of the roof eave that covers the rafter tails. Fascia is the vertical board attached to the rafter ends that holds the gutter.
How wide should soffit be?
Soffit width matches your roof overhang. Most homes have soffits between 12 and 24 inches wide. Measure from the wall to the outer edge of the eave.
How many screws per linear foot?
Plan for about 3 screws per linear foot of fascia and 4 to 6 fasteners per linear foot of soffit channel.
Should I install vented soffit?
Vented soffit is highly recommended in most climates. Proper attic ventilation prevents moisture buildup, ice dams, and extends the life of roofing materials.
Is the Soffit and Fascia Calculator accurate?
The Soffit and Fascia Calculator applies the standard formula for soffit and fascia. Accuracy is limited only by your input precision. For decisions with material consequences, use the result as a starting point and verify with a qualified professional or the relevant official source.
Is the Soffit and Fascia Calculator free?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads that appear around the tool but not inside the calculation flow.
Are my inputs saved?
No. Inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but does not see what you type into the form.
Can I use the Soffit and Fascia Calculator on my phone?
Yes. The tool is responsive and tested on iOS Safari, Android Chrome, and major desktop browsers. Touch targets meet Apple's 44pt and Google's 48dp minimum guidance.
How do I report a bug or suggest improvement to the Soffit and Fascia Calculator?
Email hi@3tej.com with the URL of this page and a description of what you saw vs expected. We typically respond within 72 hours and update calculators when rules or formulas change.
How accurate is the Soffit and Fascia Calculator?
It applies the standard formula. Accuracy is limited only by your input precision. For decisions with material consequences (taxes, medical, legal, structural), use the result as a starting point and verify with a qualified professional in the relevant field.
Is the Soffit and Fascia Calculator free to use?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads around the tool but not inside the calculation flow.
Are my inputs saved anywhere?
No. All inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but the analytics never see what you type into the form.
Does the Soffit and Fascia Calculator work offline?
Yes. Once the page has loaded, it works without internet. The calculation runs in JavaScript on your device.
Can I share results from the Soffit and Fascia Calculator?
Take a screenshot or copy the output. The page doesn't generate shareable URLs for specific calculations - inputs stay in your browser only.
Why are the results different from another soffit and fascia tool?
Most likely: different formula assumptions, different default values, different rounding rules, or different applicable rates. Check the methodology if both tools document it. Both can be valid for different scenarios.