Weld inch calculator.

Diameter-inches (DI) for a piping scope from NPS and weld counts, with socket-weld factor and total weld length.

Method

How it's calculated.

A diameter-inch (DI) is one inch of nominal pipe size welded once. A butt weld on NPS 6 pipe counts as 6 DI; ten of them are 60 DI. Contractors use DI to measure welding scope, set productivity norms and track progress.

DI = Σ (NPS × butt welds) + f × Σ (NPS × socket/fillet welds)

The tool also gives total weld length (π × OD per weld) and inch-mm (DI × wall thickness in mm for the chosen schedule), a measure some contracts use to reflect heavier walls.

Related reading: diameter-inches explained. Next step: estimate the welding hours.

Estimates for planning and education only. Verify against the applicable code edition, manufacturer data and a competent engineer.

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