This page explains the measurement or planning assumption behind the result. When you need the project quantity itself, use Board & Batten Spacing Calculator.
Clear gap is the visible open bay
If adjacent battens are 2.5 inches wide and the open space between their faces is 15 inches, the clear gap is 15 inches. That is usually the visual proportion homeowners compare when deciding whether a pattern feels dense or open.
On-center includes one batten width
The center of one batten to the center of the next spans the open gap plus one full batten width. With a 15 inch clear gap and a 2.5 inch batten, on-center spacing is 17.5 inches. Confusing these two definitions can shift every mark.
Edge treatment changes the number of spaces
With a batten flush at both boundaries, n battens create n−1 clear interior gaps. With equal open end spaces, n battens create n+1 equal clear spaces because the two wall-edge gaps are included. The same wall width and batten count therefore produce different exact gaps.
A target gap is a preference, not the solved answer
A wall cannot use a fractional batten count. In target-gap mode the useful workflow is to test whole counts, calculate each feasible exact gap and choose the one closest to the target. The final mark plan must use that exact solved spacing rather than the desired number.
Calculate marks from one reference edge
Displayed fractions or decimals are rounded for reading. If each new position is created by adding the rounded display value to the previous mark, the rounding error can accumulate. Instead calculate each start or center mark from the original datum using the full-precision solved spacing.
Decorative spacing is not structural support spacing
Board-and-batten is a visible trim-layout problem. Wall furring and framing use spacing selected from an assembly, substrate, fastener, product or applicable requirement. A visually pleasing decorative bay should never be substituted for a required support layout.
Planning workflow
Choose the spacing definition
Decide whether your design target means clear face-to-face gap or on-center repeat.
Choose edge treatment
Decide whether the pattern begins/ends with battens or with equal open spaces.
Use a whole batten count
Let target mode choose a nearby feasible count or enter the fixed count you want.
Use the exact solved gap
Treat the target as a preference and the solved gap as the layout number.
Generate positions from one datum
Keep full precision internally and round only the displayed mark values.
Separate decorative and support layouts
Do not transfer decorative spacing into furring, stud or siding-support requirements.
Example: same battens, two spacing definitions
If a wall layout has 2.5 in battens and an exact 15.1875 in clear gap, the adjacent centers are 17.6875 in apart. Calling both numbers “spacing” hides a 2.5 in difference on every bay.
Reference table
| Quantity | Includes batten width? | Measured between |
|---|---|---|
| Clear gap | No | inside face to inside face |
| On-center spacing | Yes | centerline to centerline |
| Start mark | n/a | wall datum to batten edge |
| Center mark | half batten added | wall datum to batten centerline |
| End space | No | wall boundary to nearest batten face |
Frequently asked questions
Is 16 inches spacing a clear gap or on-center?
The phrase is ambiguous without a definition. Enter a target clear gap only when that is what you mean; if a source specifies on-center spacing, convert or plan using that definition explicitly.
Why does changing batten width change on-center spacing?
Because on-center equals clear gap plus the batten face width. A wider batten occupies more of each repeat interval.
Which edge treatment is correct?
Neither is universally correct. Choose the visual termination that matches the room and trim boundaries, then keep that assumption visible in the layout.
Can I round every gap to the nearest eighth and step across the wall?
It is safer to calculate each position from the same datum using full precision, then round each individual mark for field readability. That prevents small rounding differences from walking across the entire wall.
Planning note: Product coverage, yield, package size, installation instructions and project requirements take priority over generic examples. Verify the exact product and project before purchasing.