How many duct hangers do I need?

For a simplified straight-run layout, place hangers at the ends of a usable run and keep the interval at or below the selected maximum spacing.

Does this determine structural hanger capacity?

No. Hanger load capacity, rod size, trapeze design and project-specific support requirements need separate engineering or specification checks.

Can I get hanger positions as well as count?

Yes. The calculator generates an evenly distributed station schedule across the usable run.

Duct support layout

Duct Hanger Count Calculator

Generate a practical hanger count and station schedule from duct run length, a maximum support interval and explicit end offsets.

Support layout inputs

Duct run length

Maximum support spacing

Start offset

End offset

Length unit

The spacing limit is a user-selected planning input, not a universal code rule. Verify support spacing against duct weight, insulation, size and project requirements.

Enter run length and support spacing.

Hanger layout result

Estimated hanger count

—

—Usable run

—Distributed spacing

—First station

—Last station

Hanger	Station	Distance from prior

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Hanger count method

The planner treats the duct run as a straight line. It places one hanger at each end of the usable run and divides the intervening distance so no interval exceeds the selected maximum.

Usable length = run − start offset − end offset
Intervals = ceiling(usable length ÷ maximum spacing)
Hangers = intervals + 1
Actual spacing = usable length ÷ intervals

Why a station schedule is more useful than a count

A count alone does not tell an installer where supports should be placed. The generated station schedule shows the start and subsequent spacing so the quantity can be checked against the intended run.

Worked example

For a 30 m run with 250 mm offsets and a 3 m maximum interval:

Usable length = 30 − 0.25 − 0.25 = 29.5 m
Intervals = ceiling(29.5 ÷ 3) = 10
Hangers = 10 + 1 = 11
Distributed spacing = 29.5 ÷ 10 = 2.95 m

Important support-design boundary

The result is a geometric spacing planner. It does not calculate rod diameter, trapeze capacity, anchor capacity, seismic bracing, structural attachment or any other load-resisting design.

Frequently Asked Questions

Can I change the spacing?

Yes. The selected maximum is the main planning control.

Why are there usually more hangers than length divided by spacing?

Because the layout includes support stations at both ends of the usable run.

Can end offsets be zero?

Mathematically yes, although real layouts may need clearance from fittings or end connections.