Free · Everyday planning calculators

Recessed Light Grid Spacing

Find equal-grid spacing and half-spacing offsets for up to three rows and columns.

  • Formula & worked example
  • Private in your browser
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

A 6 × 4 m room with three rows and two columns uses 2 m spacing in both directions.

Spacing = room dimension / count; outer offset = spacing / 2

Worked example

Enter these known values and leave the other values blank.

Surface length (A)
6 m
Surface width (B)
4 m
Rows of lighting fixtures
3
Columns of lighting fixtures
2
Outer row offset (a==o==)
100 cm
Row spacing (a==i==)
200 cm
Outer column offset (b==o==)
100 cm
Column spacing (b==i==)
200 cm

Assumptions and limitations

  • Rows divide the room length and columns divide the width. Centered lights use the separately displayed centerline offsets. This is geometric spacing only; fixture photometry, required illumination, wiring and structure need separate design.

Common questions

What does this estimate assume?

Rows divide the room length and columns divide the width. Centered lights use the separately displayed centerline offsets. This is geometric spacing only; fixture photometry, required illumination, wiring and structure need separate design.

Can I find a missing input?

Clear the unknown field and enter compatible known values. The controls retain supported inverse calculations, while rounded counts and one-way outputs stay directional.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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