1. Measure the outside diameter of both tubes
Use calipers across the outside of the tube, keeping the jaws square to its axis. Measure in more than one direction and at more than one position. If readings differ noticeably, check for ovality, a seam, coatings or distortion before relying on a circular template.
Cut tube OD is the tube whose end you will notch. Mating tube OD is the tube it rests against. This tool currently requires the cut tube to be no larger than the mating tube. For an opening in the mating tube, use the separate Main tube opening tool.
2. Do not substitute the nominal pipe size
A nominal pipe size is a designation, not necessarily the measured outside diameter. Entering a trade size as if it were the OD can give you a template that does not wrap correctly. Use the actual measurement or a verified dimensional specification for the exact product.
Do not use the bore or inside diameter. This version traces the intersection of the two outside surfaces; wall thickness, bevel and weld clearance are not included.
3. If calipers will not reach, measure circumference
Wrap a flexible tape or a narrow, non-stretching strip around the tube, square to the axis. Mark the overlap, lay the strip flat and measure its length. Estimate outside diameter as circumference divided by π.
For example, a circumference of 119.6947 mm corresponds to an OD of approximately 38.1 mm. A skewed wrap or a stretching tape changes the result. Cross-check the measurement before cutting.
4. Measure the included angle between centerlines
90° means the two tube axes are perpendicular. Use the angle between the centerlines, not the angle of a saw blade, a bevel or the edge of the paper. This version accepts 15° to 90° and assumes that the centerlines intersect without offset.
For a 60° joint, enter 60. If your drawing instead gives the departure from perpendicular, convert it first: a 30° departure from 90° corresponds to a 60° included angle. Check what the drawing actually labels; do not subtract every angle from 90°.
Use the side-view sketch and optional 3D preview to check the arrangement. Their displayed tube lengths are illustrative, not cut lengths.
5. Enter dimensions and cross-check the result
Choose millimeters or inches before entering the measurements. Inches accept decimals and fractions, including 1.5, 1/2 and 1 1/2. Switching units preserves the physical dimensions.
Example: cut tube 38.1 mm, mating tube 50.8 mm, included angle 60°. These diameters equal 1.5 in and 2 in. The wrap length should be approximately 119.69 mm (4.712 in). Enter the values in the calculator and compare its wrap length with the tube circumference.
The flat preview is not shown at physical scale. Once the setup is correct, choose a supported paper size and check the printed calibration marks before using the template. This Free Beta requires no account. Jobs remain in this browser; you can download a JSON backup, but this version cannot import one.