Cedar Siding Calculator
Estimate cedar siding area, exposed courses, board count, linear footage, corner trim, starter strip, and fasteners from real wall and gable dimensions.
★Project presets
⚙Siding inputs
Add all same-profile wall lengths together.
Subtract full opening area before waste is added.
Use for window casing, frieze, skirt, or water table trim.
Cedar siding takeoff
Full breakdown
▦Cedar material and spec grid
▣Reference tables
| Profile | Typical exposure | Coverage formula | Common allowance |
|---|---|---|---|
| Bevel clapboard | 5 to 7 in | Area divided by reveal | 8 to 12% |
| Rabbeted lap | 6 to 8 in | Area divided by reveal | 10 to 12% |
| Tongue and groove | Actual face width | Area divided by coverage face | 6 to 10% |
| Board and batten | Board width minus gap | Area divided by effective width | 10 to 15% |
| Cedar shingles | 4 to 5-1/2 in | Area divided by exposure | 12 to 18% |
| Cedar selection | Best use | Layout note | Install note |
|---|---|---|---|
| Clear vertical grain | Premium walls | Low movement | Keep reveals uniform |
| Select tight knot | Cabins and garages | Sort knots before layout | Back-prime ends |
| No. 1 shingles | Gables and accents | Blend bundles | Use double starter |
| Rainscreen assembly | Wet climates | Add furring thickness | Use longer fasteners |
| Fastener condition | Recommended fastener | Spacing basis | Calculator treatment |
|---|---|---|---|
| Horizontal lap | Stainless ring-shank nail | One or two per stud | Courses by stud lines |
| Shingles | Stainless box nail | Two per shingle | Higher fastener factor |
| Board and batten | Stainless siding nail | Each board at rails | Area plus line spacing |
| Coastal exposure | 316 stainless | Per local wind zone | Add manual allowance |
| Project type | Typical size | Profile match | Planning note |
|---|---|---|---|
| Accent gable | 80 to 160 sq ft | Shingles or bevel | Waste rises at rake cuts |
| Garage wall set | 350 to 650 sq ft | Lap or channel | Subtract door openings |
| Cabin exterior | 700 to 1200 sq ft | Board and batten | Confirm batten coverage |
| Full re-side | 1200 sq ft plus | Bevel or T and G | Batch boards by wall |
ℹLayout notes
Cedar siding is different than other building materials, so take some time to think through your project. I made a calculator to help you figure out how much material you need for the trim, gables and walls. It factor in board profile, reveal size, openings and waste. It also transforms those complicated variables into an easy-to-understand shopping list prior to cutting anything.
Many homeowners make a common mistake. They measure their house in square feet and divide by board width. They fails to take into account the most important part of a cedar installation: the exposed reveal. With beveled clapboard, the bottom of each board overlap the top of the next one down. That means when installed, amount of visible wood is typically an inch or two shorter than the width of the entire board. Because of that overlap, simply ordering by total square footage (not taking into account the overlap) will result in running short. By entering the actual weather exposure instead of the nominal board size, the tool allow you to order linear footage that covers area of your walls, not just the raw volume of lumber.
How to Plan Your Cedar Siding Project
Intuition also fails with waste factors. People tend to underestimate how much waste will be involved in cutting around gable ends and corners. For example, if it’s a simple rectangle wall with no openings, maybe just five percent additional material are needed for end cuts. But a front gable with steep rake edges will have much higher scrap waste. Even worse, shingles create even more waste, each shingle must be cut to a certain angle along the roof line. You can set the waste allowance anywhere between five percent (for something as simple as a rectangle) and twenty percent (for a job with many tricky angles). If your home sports lots of architectural detail, bump that number up toward 20 percent.
You’re better off overbuying boards initially rather than waiting several weeks to get a partial shipment when you run out. The moisture content of the lumber is a big factor in appearance of your siding over time. Because cedar comes out of the mill at a specific moisture content, it adjust to the climate where it’s installed, expanding and contracting accordingly. Installing your cedar when it’s already dry (typically 12-15% moisture content) reduces that motion. Wet lumber will shrink while curing, causing those unsightly gaps to open between boards. Back-priming all of your field cuts with an oil or stain will reduce this problem. The porous wood grain will seal off against quick moisture absorption, keeping your fastener lines clean and your lap joints tight.
One detail is too often overlooked: rust will permanently stain cedar siding. If you are on salt roads, or in a seaside location, standard galvanized fasteners will bleed orange streaks down your wall in just a few seasons. For lasting results, choose stainless. Grade three-one-six for severe conditions.
It calculates how many fasteners is needed based off your siding profile and stud spacing. It reminds you that lap siding may require as little as one nail every other board (or none at all) depending on your wind zone. Shingles must has two each time. Proper fastening preserves the look of the wood and prevents costly callbacks later.
On the page it breaks it all down with a reference table. The math is easy enough. You’ll see the coverage formulas laid out where you can check the math and understand how they came up with the number. They break it down by common profiles: bevel, lap, tongue and groove, and shingle.
Knowing the difference allows you to select the best profile based on your home’s architecture and climate. For example, board and batten would look great on a cabin, but it need to have exact spacing or water will get trapped inside. A shingle provides great water drainage but takes a boat load of cutting time and labor. Selecting a profile should of take into account the look you want, yes…but also the weather where you live and your skill set.
Siding with cedar also means investing in lumber; and patience. Measure carefully, account for windows/doors and add some waste: it’s not the place to hurry. Open each bundle off the truck and check moisture content. Organize boards by length & knots; then when you’re on the ladder, use the best straightest ones on the most public walls. Reserve shorter cut boards for those tucked behind eaves or in the corners. Let the calculator do the math, while you concentrate on the craft.
If done properly, all that wood will weather into a silver gray that stands the test of decades. It rewards the care given during the planning stages. Good planning = finishing strong, with no rush orders, no gaps, and plenty of leftover boards for future trim work.
