Rectangular duct
A = 2(W + H)L
A is developed sheet area; W and H are duct dimensions; L is straight length.
Existing engineering calculator
Duct Weight Calculator
Estimate the sheet-metal area, weight per metre and total weight of a straight rectangular or circular duct. Use it for preliminary fabrication, handling and support-planning checks.
Calculator inputs and result
Select the duct geometry, then enter the straight duct dimensions, sheet thickness and material. Results update for valid input values.
Choose a commonly fabricated duct-sheet material. Verify the supplied density for project material, coating and temperature.
Engineering knowledge
Duct sheet area, thickness and material weight
The weight of a straight sheet-metal duct is obtained from its developed surface area, material thickness and material density. This helps preliminary fabrication planning, handling studies, transport estimates and support-load assessments. A complete installed duct system can weigh more because of flanges, stiffeners, reinforcements, gaskets, insulation, coatings and accessories.
Related calculation knowledge
Use plate geometry and density consistently. Material density is an estimate and should be verified where procurement, structural design or a final bill of material depends on the result.
Read the Plate Weight Calculator guidance →Input and result definitions
Duct geometryRectangular ducts use width and height; circular ducts use internal diameter.
Sheet inputsLength and thickness are entered in millimetres; selected material supplies the existing density value.
ResultThe result reports sheet surface area, weight per metre and total straight-duct weight.
Formula and calculation method
Circular duct
A = πDL
D is duct diameter and L is straight length; end caps are not included.
Sheet weight
m = A × t × ρ
t is sheet thickness and ρ is material density. The calculator converts millimetres to metres internally.
Assumptions and limitations
- The calculation is for straight duct sheet only; joints, turnings, fittings, flanges, stiffeners and supports are excluded.
- Use actual material density and thickness where a final fabrication or structural decision depends on the result.
- Dimensions should represent the intended duct geometry consistently.
- Final support, handling and structural design requires project-specific loads, codes and qualified engineering review.
Illustrative use case
For a 1,500 mm × 1,200 mm rectangular duct, 2,500 mm long, using 3 mm steel at 7,850 kg/m³, the implemented relation gives 13.500 m² sheet area and approximately 317.93 kg total sheet weight, or 127.17 kg/m. This excludes the weight of connection and support details.
Frequently asked questions
Does the result include duct flanges and stiffeners?
No. Use the Flange Weight Calculator and add the relevant fabrication details separately.
Is insulation included?
No. The calculator uses the selected sheet material only. Insulation, cladding and lining must be assessed separately.
Can this be used for final support design?
No. It is a preliminary sheet-weight estimate. Final support design must include the complete installed load case and applicable project requirements.
References
- Oberg, E., Jones, F. D., Horton, H. L. and Ryffel, H. H. Machinery's Handbook. 30th ed. Industrial Press. 2016.
- American Institute of Steel Construction. Steel Construction Manual. 15th ed. AISC. 2017.
This is an original educational summary. Verify project material data and fabrication allowances for actual work.
Review information
Content type: existing engineering calculator with knowledge module.Interface reviewed: 27 August 2026. Technical review is required before project use, procurement, construction, operation, compliance or safety decisions.
Engineering disclaimer
Educational and preliminary engineering-reference use only.This calculator does not replace project specifications, detailed design, fabrication drawings, applicable standards or review by a qualified engineer. Verify all values, assumptions and decisions for actual service conditions.