Equal Spacing Calculator – Slats, Battens & Balusters
THE HANDYMAN HUB · FREE CALCULATOR
Equal Spacing Calculator
Set out slats, battens and balusters with clear end-gap options, diagrams and exact marking positions.
YOUR ESTIMATE
Your spacing layout
Clear gaps, centre spacing, individual positions and optional purchases.
Enter your opening and member details, then calculate.
Inputs changed. Calculate again to update your layout.
OPTIONAL BUSINESS TOOL
Turn your spacing estimate into a professional quote
Use the Handyman Hub Quote & Invoice Generator to create customer-ready quotes and invoices. Add your checked materials, labour and business details, then print or save your finished document.
- Professional quotes and invoices
- Your business and customer details
- Clear labour and material items
- Print or save as PDF
$4.99 one-time payment
Lifetime access · No subscription
Secure purchase through Gumroad. This separate product is optional. The calculator and its estimate printout remain free, without an account or email signup.
Set out equal gaps between slats, battens and balusters
This equal spacing calculator helps distribute matching members across a measured opening. Enter the clear opening, actual member width and either a member count or a maximum internal gap. Choose equal end gaps, flush ends or your own left and right clearances. The result shows a diagram, clear gaps, centre spacing and individual marking-out positions.
Use it for decorative timber slats, wall battens, screens and a specified baluster layout. It calculates horizontal distribution only. It does not determine whether a member, opening, fixing or guard is suitable for a safety-critical application. No universal maximum safety gap is assumed.
Measure the opening and actual width
Opening width is the clear distance between the two boundaries that the layout must fit. Measure where the members will actually be installed. If the boundaries are not parallel, check more than one height and resolve the construction detail before choosing a single value. The calculator models a constant-width rectangular opening.
Member width is the face dimension projected across that opening. It is not the thickness extending away from the wall and it may differ from the nominal timber size. Use measured or specified finished dimensions. Angled members require their actual projected width for this one-dimensional layout; the tool does not calculate a rotated member's geometry.
Choose how the ends should look
Equal-end-gap mode uses the same clear gap at both boundaries and between every member. There are one more gaps than members. For nine 50 mm members in a 1,000 mm opening, the remaining 550 mm is divided into ten gaps, giving 55 mm. The first member begins 55 mm from the left boundary and the last ends 55 mm before the right boundary.
Flush-end mode puts the outside edges of the first and last members against the boundaries. Only the spaces between members remain, so there are one fewer gaps than members. The same nine members in the same opening produce eight 68.75 mm gaps. At least two members are required for this convention.
Custom-end mode reserves your entered left and right clearances first, then distributes the remaining space between members. The end gaps may differ from each other and from the internal gaps. This is useful when a border or adjoining feature needs a specified clearance. It still requires at least two members.
Exact count or maximum gap
Exact-count mode answers the question, “What gap will this number of members produce?” If the members and fixed end gaps cannot physically fit, the calculator rejects the layout. It will not silently shrink the member width or report a negative space.
Maximum-gap mode answers, “What is the fewest number of members that keeps internal clear gaps at or below this value?” The count is rounded upward as needed, then the actual gap is recalculated. A maximum of zero requires a layout that can fit without a residual gap; it is not a command to squeeze extra material into an undersized opening.
For equal-end-gap mode the end gaps are the same as the internal gap and therefore meet the entered maximum too. For flush and custom modes, the maximum applies to internal gaps. Custom end clearances remain exactly what you entered even if they exceed that maximum. The output lists them separately to make this visible.
Clear gap versus centre spacing
Clear gap is the unobstructed distance between member edges. Centre-to-centre pitch adds one member width to that gap. Confusing those dimensions can substantially change the appearance and number of pieces. The marking-out schedule therefore provides left edge, centre and right edge positions for each member.
Every position is measured from the same left opening boundary. Use those cumulative coordinates rather than repeatedly adding the rounded displayed pitch. Internal calculations keep more precision than the printed values, and the final right edge reconciles to the opening minus the right clearance. Repeated rounding during marking can accumulate an error at the far end.
Several openings and repeated bays
The basic input handles one opening with a copies field for identical bays. Enable bulk openings to enter several different widths without changing the shared member width and spacing method. Use three comma- or tab-separated columns: name, opening width and copies. Do not include a heading row or a comma within a name.
Each opening is solved independently. Maximum-gap mode may give different member counts for different widths. Exact-count mode applies your chosen count to every opening, while each gap changes to suit that opening. Copies multiply the installed member total but do not change the positions within one bay. Disable bulk mode to return to the retained single-opening values.
When changing metric millimetres to imperial inches, the normal measurement fields convert. Bulk dimensions should be checked in the selected unit before calculation; the bulk-entry instructions identify the units. A project name can explain a group of bays on the printed report.
Optional spare members and fixing packs
Enable member purchasing if you want to add a spare percentage, deduct matching whole members already owned and enter a price per complete member. The count is increased by the spare allowance and rounded to whole members before owned stock is deducted. It does not produce a stock-length cutting plan or calculate vertical member length.
Price must be for one complete usable member of the specified length and finish. Do not enter a price per metre in that field. If you are cutting pieces from longer stock, use a separate cutting estimate and place its assessed cost in the job costs instead of pricing the same pieces twice.
Fixing packs are also optional. Enter the specified fixings per installed member, extra fixings, pack size and usable whole packs owned. Spares do not attract installation fixings automatically. The total requirement rounds to complete packs before owned packs are deducted. The calculator does not choose a fixing pattern or structural connection.
Costing and printing
Active member and fixing purchases contribute their entered prices. The optional job-cost section adds labour hours, hourly rate and other whole-job costs. Its markup applies to the active total cost, followed by entered tax. Prices start at zero and currency selection changes the displayed symbol without exchange-rate conversion.
Turning an option off excludes its quantities or costs while retaining the entries for later use. Closing a details panel only folds the view and retains active values. After changing an input, calculate again before printing so the report matches the current layout.
The free print preview contains every opening diagram, marking schedule and active purchase detail. It requires no signup. The separate paid Quote & Invoice Generator is optional if you later want a customer-facing document.
Equal spacing FAQs
What is the difference between a gap and pitch?
Gap is the clear space. Pitch is member width plus gap, measured between corresponding points such as centres.
Why do equal and flush ends give different answers?
Equal ends have count plus one gaps. Flush ends have count minus one internal gaps and zero end clearance.
Does maximum gap control custom end clearances?
No. It controls internal gaps. Custom end clearances stay as entered and are reported separately.
Can one member be centred in an opening?
Yes, in equal-end-gap exact-count mode. Flush and custom-end modes require at least two members.
Can I calculate several different openings?
Yes. Enable bulk openings and enter name, width and copies on each line. Shared width and spacing settings apply to every row.
Does it approve balustrade safety?
No. Use the specified member sizes, gaps, fixings and applicable requirements. The tool only distributes dimensions.
Are owned members included in installed quantities?
Yes. Owned stock reduces new purchases only; it does not remove members from the layout or fixing requirement.
Related free calculators
Turn equal spacing into a checked materials schedule
Record whether the layout starts with a fixed member count or a maximum entered gap, and check both end conditions. Use actual member width when reviewing the position schedule. A geometric gap comparison does not establish that guarding or fixings satisfy a project specification.
Use the wall panelling calculator for a decorative wall schedule and the timber calculator for separate stock quantities. A raised structure can be coordinated in the freestanding raised playhouse planner. If this spacing estimate already includes member purchases, carry those quantities into the project only once.
Worked example and planning guide
See the inputs, checked quantities and practical limitations in our Equal Spacing: Gaps, Centers and End Allowances guide.