calctricFrom input to answer.
- Open All Tools → Light Layout. Choose a grid or row arrangement.
- Enter room dimensions with the displayed units. For feet/inches entry, include feet marks; a bare number represents inches.
- Choose the number of rows and centres, then the wall-spacing method.
- Read the diagram and individual centre marks from the selected reference corner.
WORKED EXAMPLE
Eight centres in a rectangular room
Enter
Use 17 ft 8 in along the row and 12 ft 6 in across the rows. Choose 2 rows, 4 centres per row and half-spacing at walls.
Read the result
Centres along each row are 26½, 79½, 132½ and 185½ in from the left. Row positions are 37½ and 112½ in from the top. A1 is therefore 26½ in across and 37½ in down.
Get more from it.
- Measure each centre from the reference edge rather than repeatedly adding a rounded spacing.
- Changing the reference corner changes the coordinate readout; confirm which corner you are using.
Know the limits.
- This is a geometric centre layout, not an illuminance, lumen or lighting-code design.
- Check joists, services, fixture clearances, manufacturer spacing and the actual lighting requirements.
Verify the inputs, applicable local requirements and real conditions. The app is a calculation aid and can contain errors. See our terms and safety disclaimer.
Common questions.
Does it tell me how many lights the room needs?
No. You choose the count; it helps position the centres for the selected arrangement.