Practical tools for measured work
Even Spacing Calculator
Evenly space any number of objects across an opening - holes, hooks, posts, anything.
How it works
How to use it: enter the total opening width, the width of each object, and how many objects you want to fit. The tool spreads them out with an equal gap at both ends and between every object, so the layout is symmetric - object height is only used to draw the diagram to scale and doesn't affect the numbers.
Formula. With count objects placed in a row, there is always one more gap than there are objects (one at each end plus one between every pair):
gapCount = count + 1gap = (opening − count × objectWidth) ÷ gapCountcenter-to-center = objectWidth + gap
Worked example. With the defaults above (opening 1800 mm, object width 30 mm, count 8): gapCount = 8 + 1 = 9; gap = (1800 − 8×30) ÷ 9 = (1800 − 240) ÷ 9 = 1560 ÷ 9 ≈ 173.33 mm; center-to-center = 30 + 173.33 ≈ 203.33 mm. Check: 8 objects × 30 mm + 9 gaps × 173.33 mm ≈ 240 + 1560 = 1800 mm, the full opening.
Current-input example
The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.
- Opening
- 1800 mm
- Object width
- 30 mm
- Object height
- 200 mm
- Object count
- 8
Primary result: Gap: 173.33 mm.
Before using the result
- Measure from the datum or reference edge described by this tool, and do not mix inside, outside and centerline dimensions.
- Keep inputs in the displayed units and preserve more precision than the final cutting or purchasing tolerance requires.
- When the result is close to a limit, verify it with a test piece, field measurement, manufacturer drawing or qualified project professional.
Limitations
This tool solves for a fixed object count only - it does not check the result against any maximum allowable gap (building-code sphere rules, safety clearances, etc.). If you need the largest gap held under a limit instead of an exact count, use a code-driven tool such as Baluster Spacing or Fence Picket Spacing.
If the requested count and width don't fit the opening (count × objectWidth exceeds the opening), the calculator returns no result rather than a negative gap - reduce the count or object width, or increase the opening.
It assumes a single straight row of identical, evenly spaced objects, not an irregular or grouped layout.
Frequently asked questions
What's the difference between this and Baluster Spacing or Gallery Wall Planner?
This is the general-purpose version of the same even-spacing math, useful any time you know exactly how many objects you want (holes, hooks, shelf pegs, evenly spaced fixtures). Baluster Spacing adds a maximum-gap mode for building-code compliance, and Gallery Wall Planner adds wall-centering logic specific to picture frames.
Why is the gap not a round number?
The gap is whatever's left after subtracting all the object widths from the opening, split evenly across every gap - it will rarely land on a round number unless your inputs happen to divide evenly. Mark the center-to-center distance instead of the gap if you want a single repeatable measurement for layout.
Does the object height matter?
Only for drawing the diagram to scale - the gap and center-to-center calculations only use opening width, object width and count. Set the height to whatever your actual object is so the preview looks right.
Related tools
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