Pipe schedule chart: OD, wall, ID, and weight per foot for every NPS size

What does a pipe schedule chart tell you?

The wall. Every pipe size (NPS) has one fixed outside diameter, and the schedule number tells you how thick the wall is inside that diameter. 2 NPS pipe is always 2.375″ outside. Schedule 40 gives it a 0.154″ wall and a 2.067″ bore, schedule 80 gives it a 0.218″ wall and a 1.939″ bore, and schedule 160 pushes the wall to 0.344″. The outside never moves, so one fitting, one clamp, and one threading die fit every schedule of that size.

The charts below are the ASME B36.10 figures that define steel pipe, and B36.19 uses the same numbers for stainless in the sizes we stock. Chart 1 is the wall thickness for every schedule, 1/8 through 12 NPS. Chart 2 works out the bore and the weight per foot for schedule 40 and 80, the two you'll actually buy. The third table is the part nobody else prints: which of those sizes and schedules are on our rack right now, each one linked to its page.

Want the story behind the numbers? Our pipe sizes explainer covers why 1/2″ pipe isn't half an inch, pipe versus tube, and black versus galvanized. This page is the chart.

What is the wall thickness for each pipe schedule?

Read across for your size and down for your schedule. Schedule 40 is standard weight and schedule 80 is extra strong at every size up to 10 NPS. At 12 NPS the two systems split: STD (0.375″) and XS (0.500″) are lighter than schedule 40 (0.406″) and schedule 80 (0.688″). The 12 NPS A106 on our rack comes both ways, so read the product title. A hyphen means that schedule isn't made in that size.

Two things trip people up here. First, a schedule number isn't a thickness: schedule 40 is 0.109″ at 1/2 NPS and 0.406″ at 12 NPS, because the standard scales the wall with the pipe. Second, the OD is the number to measure. If your caliper reads 1.315″, you're holding 1 NPS, whatever the drawing calls it, and the DN sizes on metric drawings are the same pipe with a millimetre label (DN 25 is 1 NPS).

What are the bore and weight per foot for schedule 40 and 80?

Bore is what's left after the wall: OD minus two walls. Weight per foot is the ASME plain-end formula, 10.69 x (OD minus wall) x wall, in pounds per foot of carbon steel, worked from the walls in the chart above. Mill tables that still print the older three-decimal walls land a few hundredths off these figures; the difference never matters at the saw. Stainless runs about 2% heavier than these numbers, and 6061 aluminum about a third of them.

Check the weight column before you order long pieces. A 96″ length of 4 NPS schedule 40 is about 86 lb, which is more than a single courier box likes to carry, so the freight rate at checkout climbs. Under 48″ gets the best parcel rates; 48-96″ still ships, just watch the rate on your real cart. If the job needs 21 ft lengths, that's a quote and a truck.

Which pipe sizes and schedules do we stock?

Every size in this table is on the rack in Dartmouth as of September 2026 and cuts to your length up to 96″ online, free, to ±1/8″. Click a schedule to open that pipe's page. A size marked quote is stocked but priced by quote because of the weight. Black and galvanized A53 cover the everyday sizes, A106 covers heavy walls and pipe made without a weld seam, 304 and 316 cover stainless, and 6061-T6 is the aluminum line. Browse the racks whole: carbon steel pipe, stainless pipe, and aluminum pipe.

What isn't here: schedule 5, 1/8 NPS, and anything threaded. We cut plain ends only. Need threads, grooves, or a schedule the rack skips? Send a quote request with the size, schedule, and count, and we'll price it; sourcing runs 2-21 days.

What does pipe cost cut to length?

Every pipe page prices by the inch of that size, schedule, and alloy, so a 12″ piece is the honest way to compare. As of September 12, 2026, the everyday pipe on the rack runs like this:

Type any length up to 96″ and the price shows before anything goes in the cart, no quote step and no login. Volume discounts of 5-15% apply automatically as the quantity climbs, and the $40 order minimum is the only floor. Order by 1pm Atlantic on a business day and your pipe is usually cut and packed the next business day. That's what normally happens, not a guarantee. Delivery is the service you pick at checkout, and pickup at the shop is free. Prices move with the steel market and update daily, so the product page is today's number; our metal prices guide has the September 2026 board for every metal.

How do you read a pipe spec on a drawing?

In the order the callout gives it: size, schedule, spec, then finish. "2 NPS sch 40 A53 grade B, black" means 2.375″ OD, 0.154″ wall, welded structural pipe, no coating. Swap in sch 80 and the OD stays 2.375″ while the wall becomes 0.218″. If the spec reads A106, it's the cousin made without a weld seam, for heat and pressure work, and the drawing usually means it. NPT threads follow the pipe name too: 1/2 NPT fits 1/2 NPS, whatever the schedule, which is the whole reason the OD never changes.

If the drawing gives a real outside diameter and a wall instead of a schedule, it's tube, not pipe, and pipe fittings won't fit it. Our angle vs channel vs tube guide covers when square or rectangle tube beats round pipe for a frame, and the weight per foot guide does the same math for solid shapes.