Steel Pipe Schedule Chart: Sch 10/40/80 Wall Thickness & Sizes

Short answer: Pipe schedule (Sch) denotes wall thickness, not diameter. Sch 10 is thin and light, Sch 40 is the standard, Sch 80 is heavy for higher pressure. This chart maps common NPS sizes to wall thickness and pressure class so you can specify the right pipe for the job.

At a Glance

What Pipe Schedule Means

Schedule is a dimensionless number that, combined with nominal pipe size (NPS), sets the wall thickness. For the same NPS, a higher schedule means a thicker wall, higher pressure rating, and more weight. Schedule alone does not give pressure – that also depends on grade and temperature – but it is the starting point for specification.

Sch 10, 40, 80 Compared

The chart shows how wall grows with schedule at fixed diameter. Sch 10 is light and low-pressure for water and ducting. Sch 40 is the all-purpose standard for plant and utility piping. Sch 80 is heavy-wall for higher pressure and mechanical load. Thicker walls also resist corrosion allowance and external damage.

Reading the Chart

Find your NPS row, then pick the schedule that meets pressure and code. Remember larger diameters need proportionally thicker walls for the same schedule. For critical service, confirm the allowable stress and join method (welded vs threaded) with the applicable standard.

Specifying Pipe with HXSCO

HXSCO supplies carbon, alloy, and stainless steel pipe across schedules and standards. See our seamless vs welded guide en tell us NPS, schedule, grade, and length; we will quote with mill-test certificates and the right approvals.

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