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Fiber-Cement Siding Plank Reveal & Course Calculator

Calculate the number of fiber-cement lap siding courses needed for a wall, based on the plank's exposed reveal height.

Siding is cladding in the UK and Australia.

  • Answers as you type
  • Every formula cited
  • Calculated in your browser
SettingsSettings for this calculationUS
Market
Imperial · sales tax
The vertical wall height to be sided, from foundation to eave.

Measure from the bottom starter course line up to the underside of the eave or soffit.

The exposed height of each installed course, after overlap.

This is not the full plank width — it's only the portion left showing once the course above overlaps the plank below, per the manufacturer's installation instructions.

Siding courses needed

18 courses

High confidence
Then change the inputs to see how far the answer moves.

Show calculation logic

How this was calculated

Formula source(s)

  • Course count = ceil(wall height ÷ plank reveal), where reveal is the exposed (non-overlapped) height of each installed course — a standard fiber-cement plank has a fixed board width, but only the reveal portion shows once overlapped by the course above

Inputs used

Wall Height (Foundation to Eave)
10 ft
Plank Reveal (Exposed Height per Course)
7 in
Final result18 courses

What this calculation does not cover

  • Any reveal can be typed in, but the plank sets a ceiling on it. Manufacturers fix a minimum overlap between courses, commonly around 25 to 32 mm, so each board width has a largest legal reveal. Divide a wall by a reveal above that and the course count cannot be installed without thinning the lap to where water gets behind it.
  • Divides and rounds up, which is the reverse of how courses get set out. Installers choose the course count first and back out an even reveal so the courses meet window heads and sills and the top course is not a sliver — the rounded-up count here leaves that part course to be dealt with on the wall, in full view along the elevation.

Estimated cost — your price

This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.

10 ft
Schematic, drawn to the proportions you entered — not to scale on screen.

Part of a bigger job

This trade is one line of a job takeoff. Run the whole job and every other trade comes back with it, off the same measurements.

Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.

Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.0.1

Regulatory standards & verification citations1
  1. Course count = ceil(wall height ÷ plank reveal), where reveal is the exposed (non-overlapped) height of each installed course — a standard fiber-cement plank has a fixed board width, but only the reveal portion shows once overlapped by the course above
Cite this page

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Tools and safety for this job

To hang siding or cladding and cut fibre-cement board. Generic types, no brands, no prices.

Protection this work requires

  • Cutting or grinding concrete, masonry, screed, tile or fibre-cement board releases respirable silica: cut wet or extract at the tool, and wear a P2/N95 respirator at minimum — a nuisance dust mask does not filter it.
  • Hardwood dust is a recognised carcinogen: extract at the tool and wear a P2/N95 respirator when cutting or sanding indoors.
  • Saws, grinders and breakers run above 85 dB, where hearing damage accumulates and does not recover: defenders or plugs for every cut, not just the long ones.
  • Most fatal falls on small jobs are from under three metres: use a tower or a ladder tied at the top, and never work off the top two rungs.
Show the 9 tools this job needs

Essential

  • Chalk line

  • Circular saw

  • Combination or framing square

  • Cordless drill/driver

  • Dust extractor or vacuum with a fine filter

  • Spirit level

  • Tape measure

  • Tower scaffold or trestles

Recommended

  • Mitre saw

Also needed as materials: chalk refill, circular saw blades, drill and driver bits, mitre saw blades.

what each cladding tool is for, and the spec that decides which to buy where one does.

Now that you have the number

These guides cover the work this quantity is for — the first ones run this calculator inside the section that raises the question.

Still deciding? Vinyl Siding vs Fiber Cement — the factors that actually differ, with no invented prices.

How to calculate fiber-cement siding plank reveal & course in 3 steps

  1. Wall Height (Foundation to Eave)The vertical wall height to be sided, from foundation to eave.
  2. Plank Reveal (Exposed Height per Course)The exposed height of each installed course, after overlap.
  3. Siding courses neededThe tool computes the siding courses needed from those figures and shows the formula, its sources, and a confidence rating alongside it.

Frequently asked questions

Why is the reveal not the same as the plank's full width?
Each course of lap siding overlaps the one below it, so only the exposed portion — the reveal — is visible on the finished wall. The reveal is always smaller than the plank's full board width.
Why does the course count round up?
A partial course at the top of the wall still requires a full course of material and installation labor, so the result is rounded up to the next whole course. Rounding up is also the safe direction whenever the reveal entered is already the widest the plank allows. A 3.00 m (118 in) wall at a 178 mm (7 in) reveal divides to just under 17; spread over 17 courses, the reveal evens out at 176.5 mm (6 15/16 in) with a little more lap. Squeezing the same wall into 16 would need 187.5 mm (7 3/8 in), leaving an 8¼ in (210 mm) plank about 22 mm (7/8 in) of lap, below the 25 to 32 mm (1 to 1¼ in) minimum manufacturers commonly set.
What reveal goes with which plank width?
The reveal is the plank's width less the lap. At a 32 mm (1¼ in) lap, an 8¼ in (210 mm) plank shows 7 in (178 mm), which is the default here, and a 6¼ in (159 mm) plank shows 5 in (127 mm). Take the lap from the installation instructions for the plank being bought: that minimum is what sets the widest reveal the plank can give.
Does this account for the starter strip or trim at the top and bottom?
No — this calculates the number of siding courses based on reveal height alone. Starter strip, frieze board, and any trim details at the top or bottom of the wall should be planned separately.
Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — a confirmed fix gets a permanent check of its own, so the same mistake cannot come back.