Use the selected unit throughout. Changing units converts your entries.
See a quick calculation example
Calculation example only: 120 in ceiling-to-floor − 84 in entered clearance = 36 in maximum planned drop. These are fictional inputs, not recommended clearance or product dimensions.
Optional: compare measurements from your selected light
Have the selected option’s drawing? Add its measurements below. If not, leave these fields blank and plan your space first.
Use the ceiling-to-lowest-point dimension from your selected option’s drawing, in the unit chosen above.
Which length should I enter?
Enter D: the full distance from the ceiling mounting surface to the light’s lowest point—not just the cable, chain or light body.
Single-suspension measuring example, not this product. Use your selected option’s assembled drawing; multi-cable and ring designs differ. For a rod-mounted light, use the full installed height of the actual rod combination; do not assume continuous adjustment. Supplied cable or chain length is not necessarily its installed length.
Generic measuring example only; not this product, not to scale and not an installation drawing.
Optional: check stair opening space
Measure between the opening’s inside edges, allowing for projecting railings. Measure the light’s widest span in the same direction.
Space on each side = (opening width − light width) ÷ 2
W: opening width. F: widest light width. g: space on each side when centred.
For a centred light only. Check the other direction and any obstacles separately; for an off-centre light, measure each side. This is not a safety clearance or fit approval.
See a quick calculation example
Calculation example only: A 120 in opening and a 30 in-wide light leave 45 in on each side if centred. If a confirmed selected-light width is available, Load example uses that width instead. This is not a safety check or product-fit verdict.
Generic measuring example only; not this product, not to scale and not an installation drawing.
