Can this infer elbow quantities from duct length?

No. It counts elbows from a schedule you enter.

Does the calculator distinguish 45-degree and 90-degree elbows?

Yes. The schedule keeps the fitting categories separate before calculating the overall planning quantity.

Can I include spares?

Yes. Enter a spare percentage and the result is rounded to a whole fitting.

Duct fitting schedule

Duct Elbow Quantity Calculator

Convert an existing duct routing schedule into separate elbow counts, a practical procurement quantity and a visible spare allowance.

Elbow schedule inputs

90° elbows

45° elbows

90° offset/elbow assemblies

45° offset/elbow assemblies

Spare allowance (%)

Accessory sets per elbowUse only when the same accessory set applies to every elbow.

This tool counts known fitting types. It does not infer elbows from duct run length or choose elbow geometry.

Enter the routing schedule.

Elbow procurement summary

Planning elbow quantity

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—Scheduled elbows

—Planning quantity

—Spare pieces

—Accessory sets

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Why a schedule-based elbow counter is useful

A routing schedule can contain multiple fitting types. Keeping them separate improves procurement control because a 90° fitting and a 45° fitting are not interchangeable just because both are “elbows.”

Scheduled elbows = 90° + 45° + offset 90° + offset 45°
Planning quantity = ceiling(scheduled elbows × (1 + spare ÷ 100))
Accessory sets = planning quantity × accessory sets per elbow

Worked example

A schedule containing 14 standard 90° elbows, 6 standard 45° elbows, 3 offset 90° assemblies and 2 offset 45° assemblies contains 25 scheduled items. With 5% spare, the planning quantity becomes 27 pieces.

What the calculator does not determine

It does not determine radius, connection type, pressure class, gauge, turning-vane configuration, reinforcement or exact fitting dimensions. Those belong to the project duct design and selected fitting specification.

Procurement recommendation

Keep the detailed schedule by fitting type even when using the total for a high-level material forecast. That prevents an apparently adequate total quantity from hiding shortages in one specific fitting category.

Frequently Asked Questions

Can I count just 90° elbows?

Yes. Set the other categories to zero.

Does an offset assembly automatically mean two elbows?

No. The calculator counts the assembly according to your schedule category.

Can spare allowance be zero?

Yes.