Pipe ISO Calculator & Offset

Pipe ISO Calculator is a piping calculator built for pipe fitters, welders, plumbers and fabrication shops.

Sketch a pipe line on an isometric grid the way you would on paper, and the app works out the numbers for you: the centerline (CL) and cut length of every pipe, the fittings the line needs, and the weld points. When the sketch is done, share it as a PDF or open it in CAD as a DXF.

■ How it works
1. Choose the connection type — butt weld, socket weld or threaded.
2. Draw the line on the ISO grid with ISO snap or free snap.
3. Enter the CL dimension of each segment.
4. The app takes off the fitting dimensions and gives you the CUT length of every pipe.
5. Check the cut list and cutting summary, then save, share as PDF or export to DXF.

■ Pipe ISO sketch
- Isometric sketch workspace with ISO snap and free snap
- Centerline (CL) and pipe CUT length for every segment
- Fitting take-off applied automatically
- Dimension table and final cut list with quantities
- Cutting summary — fitting quantity, weld points (diameter-inch), total pipe cut and total length
- Required fittings listed by size and type
- Edit segment dimensions at any time
- Line name, sketch number, title block and drawing notes

■ Connection types
- All butt weld — ASME B16.9 fittings
- Small-bore socket weld — ASME B16.11, Class 3000
- Small-bore threaded — ASME B16.11, Class 3000
- Choose the small-bore limit: ≤1", ≤1-1/2" or ≤2" (above it, butt weld is used)
- Change the joint type of any point later
- Joint symbols for butt weld, socket and threaded shown on the sketch

■ Offsets and miters
- 45° offset — offset, travel and cut
- Rolling offset — E-W / N-S / U-D, travel and cut
- 90 + 45 offset — advance, offset and travel
- 3D offset
- Elbow miter cutting

■ Pipe and fitting dimensions
- Pipe and fitting dimension tables — ASME and KS/JIS
- Elbows, tees, reducers and more, by size

■ Export and save
- Create and share PDF — send the sketch and cut list to the shop, the foreman or the client
- Export DXF to open the drawing in CAD (Pro)
- Save and load sketches on your phone
- mm / inch

■ Built for quick checks on site
Made for the moment before you cut, fit up or hand over a work sketch — when you need a reliable number fast and don't have time to work it out by hand.

■ Free and Pro
- Every tool can be used 3 times a day for free.
- Pro (one-time purchase, no subscription) removes the daily limit and unlocks DXF export.
- No ads.

■ Feedback
Missing a fitting, a standard or a tool you use on site? Tell us with "Rate App / Send Feedback" in the app — new features come from field requests.

Recent changes:
• Added parallel pipe offsets for 2–4 pipes with custom angles and overall dimensions.
• Improved angle correction, horizontal/vertical guides, hatching and fitting placement.
• Added dashed line previews and drag-to-size notes.
• Updated fitting illustrations and simplified menus.
• Free: 5/week each for elbow miters and 2D offsets; PDF/DXF share 5/week. Resets Monday.
• PDF exports have no watermark.
• Pro: monthly/yearly plans with unlimited use. Existing lifetime purchases remain valid.