Notch depth and cut length calculator

Get the notch depth and cut length before notching for any tube size, angle and offset, with tips trimmed to leave enough wall to weld.

Notch depth and cut length calculator

Find how deep a notch goes and how long to cut the tube before you notch it, so it doesn't come up short.

Tube you're notching (OD)Inches. For pipe, enter the actual OD (1" NPS = 1.315").

Wall thicknessOf the tube you're notching. Used to trim the tips on angled notches.

Tube it joins (OD)Must be the same size or larger.

Angle between tubesDegrees. 90 = square. Use the smaller angle of the joint.

Offset from centerInches. 0 = tubes centered on each other.

Center-to-center lengthAlong this tube's centerline, from the center of the tube it joins to the far end.

Other end of the tubeFor a square-cut end, measure to the end of the tube.

Notch depth (trimmed tips to valley)–

Trimmed tips sit this far from the joining tube's centerline–

Cut length (before notching)–Enter a center-to-center length

Cut the tube square to the length shown, then notch it — the square-cut end becomes the flat on the trimmed tips. Measure twice before you cut a whole stack — tube OD can be a few thousandths off nominal.

How to use the notch depth calculator

Enter the OD and wall thickness of the tube you're notching.
Enter the OD of the tube it joins, the angle between the tubes, and any offset.
Enter the center-to-center length and choose what the other end looks like to get your cut length.

What the numbers mean

Notch depth is the distance from the flat on the trimmed tips down to the bottom (valley) of the notch.
Tip distance is how far the trimmed tips sit from the centerline of the tube you're joining. It comes off your center-to-center length once for each notched end.
Cut length is the length to cut your tube square before you notch it.

Why the tips are trimmed

A full-depth notch leaves the tips as thin as a knife edge, with nothing left to weld. So the calculator trims them back. On 90° notches, the depth is about one third of the tube OD, rounded up to the next 1/8". On angled notches, the long point is trimmed back to where the hole saw just reaches the inside wall of the tube at the start of the cut. Rounding up to the next 1/8" keeps cut lengths to easy numbers and errs toward cutting a little more, not less.

Measuring center-to-center

Measure along the centerline of the new tube, from the center of the tube it joins to the center of the tube at the other end. If the other end is cut square, measure to the end of the tube instead.

Frequently asked questions

How much shorter do I cut a tube notched on both ends?

For 1-3/4" tube notched onto 1-3/4" tube at 90°, the trimmed tips sit 1/4" from each joining tube's centerline. So you cut the tube 1/2" shorter than the center-to-center length.

Why do my notched tubes keep coming out short?

Usually the length was measured between the outsides of the tubes and the full notch depth was taken off on top of that. Measure center-to-center and let the calculator work out the cut length.

What if the tube I'm notching is smaller than the one it joins?

The notch is shallower and the tips usually have plenty of wall already, so often no trimming is needed. The calculator tells you when that's the case.