Practical tools for measured work
Hopper / Bin Flat-Pattern Developer
Develop four printable trapezoid panels for a centered rectangular hopper inlet and outlet.
Calculate the layout, check the diagram, then print the result for the shop or jobsite.
Add the entered allowance outside the theoretical blue outline in the direction required by your seam detail.
How it works
Measure inlet and outlet at the theoretical fold lines, not across an existing flange. A centered hopper develops into two matching pairs of trapezoids.
Worked example: a 700 by 500 mm inlet, 200 by 150 mm outlet and 600 mm vertical height gives true panel heights of 625.0 mm and 650.0 mm. Check the PDF calibration square before transferring the outline.
Current-input example
The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.
- Hopper inlet width
- 700 mm
- Hopper inlet depth
- 500 mm
- Outlet width
- 200 mm
- Outlet depth
- 150 mm
- Vertical height
- 600 mm
- Edge allowance
- 15 mm
Primary result: Wide-face true height: 625.00 mm.
Before using the result
- Measure from the datum or reference edge described by this tool, and do not mix inside, outside and centerline dimensions.
- Keep inputs in the displayed units and preserve more precision than the final cutting or purchasing tolerance requires.
- When the result is close to a limit, verify it with a test piece, field measurement, manufacturer drawing or qualified project professional.
Limitations
This supports centered rectangular inlet and outlet geometry. It does not determine capacity, flow angle, material gauge, stiffeners, bend deduction or weld details. Make a test panel when finished dimensions are critical.
Frequently asked questions
What should I verify before using this result?
Recheck the physical measurements, confirm that every input uses the displayed unit, and compare the result with the applicable drawing, product specification, code requirement or test piece.
Why might the finished result differ?
Real work can include thickness, kerf, seams, tolerances, hardware allowances, installation clearances or site conditions that are outside the calculation. The limitations section identifies the main exclusions for this tool.
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