Measure soffit coverage with flexible units and sections. Get gross, net, and waste-added areas. Plan panels, fasteners, and costs with confidence for any project.
Sample scenario shows typical inputs and outputs for budgeting.
| Method | Perimeter (ft) | Width (ft) | Openings (ft²) | Waste (%) | Net (ft²) | With Waste (ft²) |
|---|---|---|---|---|---|---|
| Perimeter × Width | 180 | 2 | 8 | 10 | 352 | 387.2 |
All calculations are done in a consistent internal unit, then converted to your chosen output units.
Exterior soffits cover the underside of eaves and overhangs. Area is typically driven by total run length and average width, but corners, returns, and porch transitions can change the footprint and should be checked on elevations.
Use the perimeter method when you have a clear building outline and a mostly uniform overhang. Use the total-length method for multiple runs or when interior and exterior soffit lines are measured separately in a takeoff package. List each run and quantity to track revisions.
Measure width perpendicular to the wall line, from fascia to wall or to the inside edge of a soffit receiver. If the width varies, break the soffit into sections and compute each section area for more reliable totals. For stepped framing, confirm the horizontal projection.
Subtract planned openings for vents, lights, speakers, access panels, and decorative grilles. For continuous vent strips, use the strip length times its cutout width, and confirm whether manufacturer net-free area requires different sizing. Many vent layouts target balanced intake and exhaust, so coordination with roof venting matters.
Add waste for cutting around hips, valleys, and irregular framing. Typical allowances range from 5% for simple rectangles to 12% for complex roofs, and can be reduced when full-length panels are staged and cuts are repetitive. If material arrives in fixed lengths, include an additional trim-loss buffer for offcut patterns.
If you know panel dimensions, convert the net area into an estimated panel count. Allow extra panels for starter pieces, color matching, and jobsite damage. Record fastener spacing and accessory lengths for accurate procurement. For example, a 0.3 m by 3.66 m panel covers about 1.10 m² before overlaps.
Keep a single input unit through the takeoff, then convert to the output unit once. Mixing feet and meters can silently distort totals. This calculator normalizes values internally, then reports area in your selected unit. When exporting, keep the same unit set across projects to support cost benchmarking.
Write down what was included: porch ceilings, gable returns, detached canopies, and any exclusions. A short notes field in the export helps reviewers validate the scope and prevents change orders caused by missed edges. Include waste rate, panel size, and opening list clearly.
For uniform overhangs, multiply total perimeter run by average soffit width. If widths vary or the building has many offsets, use the section method to total each run separately.
Yes. Subtract the cutout area for vents, lights, speakers, and access panels. If openings are small and frequent, you can group them by type and multiply by quantity.
Use about 5% for simple rectangles, 8% for moderate hips and returns, and up to 12% for complex rooflines. Increase waste if panels come in fixed lengths and layouts are irregular.
Panel count equals net area divided by panel coverage area. Round up to whole panels, then add extras for starters, color consistency, and damage. Manufacturer overlap rules can reduce effective coverage.
They should not, aside from rounding. Enter values in one unit system and avoid mixing. The calculator converts inputs to a base unit internally and then converts the final area to your chosen unit.
Yes, if you approximate the curve with measured arc length and an average width. For higher accuracy, break the curve into short segments and use the section method.
If openings exceed gross area, the net area is clamped to zero. Recheck opening sizes, confirm width units, and ensure you selected the correct method before exporting.
Accurate soffit quantities reduce waste and keep crews moving.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.