An online tool for installers: it shows where to put the marks and how many millimetres to cut so a straight tray can be bent on site — no factory bends or fittings needed. It handles turns, offsets and vertical bends, and draws the job up with dimensions.
A triangular wedge is cut in the base: the tip sits on the outer edge, the opening on the inner edge. The side that ends up inside the turn is cut through its full height; the outer side is left alone and bends by itself. The size comes from the tray width and the angle. For 300 mm tray at 45° that is 124 mm either side of the bend line, so 248 mm of full opening. For 200 mm tray at the same angle it is 83 mm each way.
Where a run has to step sideways and carry on parallel — around a beam or a duct, say — two cuts are made facing each other, on opposite sides of the tray. The key figure is not the cut itself but the distance between the notches: it allows for the metal removed by the cut. Without that allowance the run will not line up. The easiest way is to measure from the edge of the first notch to the centre of the second.
To lift or drop a run, a wedge is cut in both sides and the base between the tips simply folds. The size comes from the height of the side, not the tray width, so the cut is several times smaller: with a 60 mm side at 45° it is about 25 mm each way. An inside bend (a dip) folds cleanly. An outside bend (a hump) needs the bottom trimming to fit or the joint welded — there is not enough metal at the edges.
A rise or drop to a set height is two vertical angles in a row. The calculator works out the length of sloped tray between them. One angle is always an inside bend and the other an outside bend, so it is worth planning the awkward one where it is easy to weld.
Cut each way from the bend line, in millimetres. Full opening is double that. Figures are for a horizontal turn, where the tray width sets the size.
| Tray width | 30° | 45° | 60° | 90° |
|---|---|---|---|---|
| 100 mm | 27 | 41 | 58 | 100 |
| 150 mm | 40 | 62 | 87 | 150 |
| 200 mm | 54 | 83 | 115 | 200 |
| 300 mm | 80 | 124 | 173 | 300 |
| 400 mm | 107 | 166 | 231 | 400 |
| 500 mm | 134 | 207 | 289 | 500 |
45° most of the time — convenient figures and simple marking out. 30° suits a gentle detour around an obstruction, 60° works in tight spots. The calculator handles any angle from 1 to 80 degrees.
For a horizontal turn, no — only the side that ends up inside the turn is cut, and the outer side bends by itself. For a vertical bend both sides are cut, identically and symmetrically about the bend line.
Because it is set by the height of the tray side, not the width. A side is usually 50–100 mm against 200–400 mm of width, so the cut is several times smaller.
From the centre of the first notch to the centre of the second — that is the main figure in the calculator, and it already allows for the metal removed by the cut. If it is easier in one go, measure from the edge of the first notch to the centre of the second; that figure is shown too.
Yes. After the first visit the page is stored in the browser and works offline, so it keeps working on site with no signal. It can be installed on a phone like an ordinary app, with an icon on the home screen.
Yes — the side height is entered by hand, so it suits tray of any profile and cable ladder too. With ladder, make sure the bend line does not land on a rung.
The geometry is exact, but it does not account for metal thickness or the radius at the fold. On thin galvanised tray the difference is within a millimetre. It is worth trying the first cut of a new size on an offcut.
Electricians and installation crews running cable tray on site: when the factory bend you need is not to hand and the run has to turn or clear an obstruction today. The tool is free, with no sign-up and no ads, and runs on a phone right there on the job.