Board and Batten Calculator — Siding Counts

Board and batten siding is a rhythm — wide boards, a deliberate gap, a narrow batten strip nailed over each seam — and ordering for it is a counting problem before it is a lumber problem or a style problem of any kind. Enter the wall width, the board’s face width and the gap you want, and this calculator returns the board count, the batten count and the linear feet to buy.

The Pitch: One Board Plus One Gap

The whole computation is a rhythm problem. Each board advances the wall by its face width plus the gap that follows it — the pitch — so the count is the wall width divided by the pitch, rounded up, with the final board ripped to whatever width closes the wall honestly. The battens then count themselves: one over each interior gap, which is boards minus one, the oldest fencepost arithmetic in construction. Two craft notes ride on the numbers. First, use the board's actual face width — a dressed 1×10 measures 9.25 inches, not 10, and planning on the nominal size drifts the rhythm by three-quarters of an inch per board until the last gap is a scandal. Second, the gap is not merely decorative: it is the expansion joint that lets wide boards move seasonally under the batten's loose side, which is why traditional work nails battens through the gap's centre, into the framing, never through both boards.

Worked Example: A Twenty-Foot Wall

The defaults lay out a 240-inch wall with 9.25-inch boards and a generous 2-inch gap. Pitch = 11.25 inches; boards = ceil(242 ÷ 11.25) = 22; battens = 21; coverage = 22 × 9.25 + 21 × 2 = 245.5 inches, the overshoot being the last board's rip allowance. At an 8-foot wall height the order is 43 pieces × 8 = 344 linear feet of stock combined. Change one input and watch the aesthetic change with the arithmetic: close the gap to half an inch and the same wall wants 25 boards in a tighter, more modern rhythm; open it to 3 inches and 20 boards carry it with a bolder, more rustic beat. The calculator's real product is that preview — pattern and purchase order from the same three numbers.

Where the Style Comes From, and Where It Goes Now

Board and batten is Scandinavian farmhouse engineering that crossed the Atlantic with settlers: vertical boards shed water by gravity, the gaps absorbed green lumber's shrinkage, and the battens — often the only sawn-thin stock on a homestead — sealed the seams against weather while letting the wall breathe seasonally. It sided barns for two centuries before it decorated suburbs. The modern revival runs it in fibre-cement and engineered wood as much as timber, reverses it (batten-under, "channel" profiles), and brings it indoors as wainscot-height accent walls — where this same pitch arithmetic governs, with painted MDF forgiving the expansion rules that exterior wood still obeys absolutely. The calculator's gap logic is the exterior logic; interior decorative versions may close the gap to zero, which the input allows.

Laying Out From the Middle

The count is only half the layout; the other half is where the rhythm starts. Professionals lay board and batten out from the wall's centreline — a batten (or a board's centre, by design choice) placed on the middle mark, the pitch stepping outward both ways — so the two ripped edge boards come out equal and the wall reads as composed rather than accumulated. Corners and openings then interrupt a symmetric field instead of a running one, and the rip widths the calculator's coverage overshoot predicts land split between the two ends. On walls with a centred feature — a gable peak, a window — the layout starts there instead. None of this changes the counts this page returns; it changes whether the counts look inevitable, which is the difference between siding and scenery.

Fastening for Movement

The counts assume the traditional fastening logic, which exists to let the wall breathe dimensionally. Each board is nailed with a single line of fasteners near its centre at each horizontal girt or furring line — one nail restraining position, the board's edges free to expand and contract within the gap the batten covers. The batten itself is nailed through the gap, into the substrate between the boards, never through both board edges: pin both boards under one batten and the next dry season splits the restrained board down its length, the style's signature failure. At girts spaced 24 inches apart, an 8-foot board takes five fasteners on its centreline — the count multiplies out of the calculator's board total for the hardware order, one of the many small arithmetics the pitch governs without appearing in it. Count the girts before the boards, and the hardware order writes itself alongside the lumber order, one line under the other.

Openings: Cutting the Rhythm Around Holes

Windows and doors do not reduce the board count by their area — they interrupt runs, and each interruption costs a ripped board on both sides plus trim. The working method prices each uninterrupted wall segment with this calculator and sums the segments, adding one board per interruption for the rip-and-trim waste. It is slower than dividing the whole elevation, and it is how the take-off survives contact with the lumberyard: the segment counts are what gets cut, stacked and carried, and a rhythm that meets an opening symmetrically (the centre-out layout again) wastes the least. Figure the openings before the order, and the calculator's clean divisions become a cutting list instead of a surprise.

Related Tools

More from the Construction Calculators hub: the Wainscoting Calculator — the indoor cousin, spacing panels instead of boards — and the Shiplap Calculator for the horizontal relative.

Frequently Asked Questions

How far apart should board and batten boards be spaced?

The gap is a design choice with a traditional band: half an inch to about 3 inches between board edges, with classic farm work near 1–2 inches (this page's default) and contemporary work often tighter or shadow-gap bold. What is not optional is a batten wide enough to cover the gap plus an inch of bearing on each board — a 2-inch gap wants a batten of at least 4 inches in theory, and the common 1×3 (2.5 inches actual) pairs honestly with gaps up to about half an inch, wider battens beyond that. Let the batten you can buy set the gap you choose.

Do the battens go on the inside corners of a building too?

Interior gaps, always — the calculator's boards-minus-one. Corners are trim's job: buildings usually close corners with corner boards (two battens meeting, or a dedicated corner trim) rather than a floating batten over a corner gap, and openings get the same trim treatment. If your design does batten every corner, add two per corner to the calculator's count — the note under the result says the same. Openings (windows, doors) break runs entirely: lay out each wall segment separately and sum, as with any siding.

What size boards are traditional?

Vertical boards of 8 to 12 inches nominal (1×8 through 1×12), with 10s and 12s the barn classics, and battens of 1×2 to 1×4. Wider boards show fewer seams and cup more readily — the reason the tradition settled where it did. Modern fibre-cement versions standardise near the same faces. Whatever the size, the calculator wants the actual face: dressed lumber runs a half to three-quarters of an inch under nominal, and the rhythm error compounds per board, as the pitch section's arithmetic shows.

How much extra should I order?

About 10% over the calculator's linear feet for a straight wall in sound stock, 15% where the wall is broken by openings or the lumber grade is rustic (knots and wane become waste by choice as much as by flaw). Battens, being thin and warp-prone, deserve the generous end of the allowance. The calculator prints net figures — the waste culture of your material and your wall belongs to the order, and the result note repeats the 10% counsel at the point of use.

Can board and batten run horizontally?

It can and increasingly does, as a design gesture — but the physics that invented it was vertical (gravity drainage, shrinkage across the width), and horizontal runs trap water on every batten's top edge outdoors unless detailed with flashing and slope. Indoors, horizontal board and batten is a purely visual rhythm and this calculator prices it identically — wall width becomes the vertical dimension of the run and the wall's height the run's length. Enter accordingly; the pitch does not care which way is up, even if the weather outside very much does care about it indeed.

What about the reverse style, batten under board?

"Reverse board and batten" (wide gaps with the batten as a recessed shadow board behind) uses the same pitch and counts, with the batten stock usually wider and thinner and the gap read as a dark reveal from the street. The calculator's board and batten counts carry over unchanged; only the batten's dimensions and the fastening logic differ. It is a useful reminder that the calculator counts a rhythm, and the rhythm survives every material and inversion the style has undergone in three centuries.