3/4 inch Double extra strong pipe

Dimensions

Published dimensions for 3/4 inch Double extra strong pipe.
Trade size	NPS 3/4 · DN 20
Schedule	Double extra strong (XXS)
Standard	ASME B36.10M (welded and seamless wrought steel pipe)
Outside diameter	1.050" · 26.67 mm · designated 26.7 mm in the metric column
Wall thickness	0.308" · 7.82 mm
Inside diameter	0.434" · 11.03 mm
Weight, plain end	2.44 lb/ft · 3.64 kg/m

Cross-check: the standard plain-end weight formula W = 10.6802 x t x (OD - t) gives 2.44 lb/ft here, 0.0% from the published 2.44 lb/ft. The published figure is the one printed above.

Why 3/4 inch pipe is not 3/4 inches

Nominal Pipe Size is a label, not a measurement. NPS 3/4 pipe has an outside diameter of 1.050 inches, and it keeps that outside diameter in every schedule made. What the schedule number changes is the wall: at double extra strong (xxs) the wall is 0.308 inches, so the bore comes out at 0.434 inches.

That is the practical consequence. Fittings, flanges, supports and threading dies are sized to the outside diameter, so they fit any schedule of the same trade size. Flow, pressure drop and anything that has to pass through the pipe depend on the inside diameter, which changes with every schedule. Order by trade size and schedule; work your hydraulics from the bore.

Other schedules in NPS 3/4

Same outside diameter of 1.050 inches throughout - only the wall and the bore move.

Every other published schedule for NPS 3/4.
Schedule	Wall (in)	ID (in)	Weight (lb/ft)
Schedule 5	0.065	0.920	0.68
Schedule 10	0.083	0.884	0.86
Schedule 30	0.095	0.860	0.97
Schedule 40	0.113	0.824	1.13
Schedule 80	0.154	0.742	1.48
Schedule 160	0.219	0.612	1.95
Standard wall (STD)	0.113	0.824	1.13
Extra strong (XS)	0.154	0.742	1.48
Schedule 5S	0.065	0.920	not published
Schedule 10S	0.083	0.884	not published
Schedule 40S	0.113	0.824	not published
Schedule 80S	0.154	0.742	not published

Frequently asked questions

What is the wall thickness of 3/4 inch double extra strong (xxs) pipe?

0.308 inches (7.82 mm). The outside diameter is 1.050 inches (26.67 mm) whatever the schedule, so this wall leaves an inside diameter of 0.434 inches.

What is the inside diameter of 3/4 inch double extra strong (xxs) pipe?

0.434 inches (11.03 mm). Inside diameter is outside diameter minus twice the wall: 1.050 - 2 x 0.308 = 0.434 inches.

Is 3/4 inch pipe actually 3/4 inches?

No. NPS 3/4 is a trade size, not a measurement. The pipe measures 1.050 inches across the outside and 0.434 inches across the bore in this schedule. Only the outside diameter is fixed across schedules.

How much does 3/4 inch double extra strong (xxs) pipe weigh?

2.44 pounds per foot plain end (3.64 kg per metre), for carbon steel. Stainless of the same dimensions runs a little lighter, and the figure excludes coatings, linings and fittings.

Where this table stops

This table runs from NPS 1/8 to NPS 24 and stops there. ASME B36.10M itself continues to NPS 80; those larger sizes are not carried here, so a size above NPS 24 is missing rather than undefined.

Where these figures come from

Dimensions are as defined by ASME B36.10M (welded and seamless wrought steel pipe). This site is an independent reference and is not affiliated with, endorsed by or approved by any standards body.

Every value on this page was cross-checked against 5 independent published sources:

ASME B36.10M pipe schedule chart - wall thickness and weights - Flange Bolt Chart, states ASME B36.10M-2018, Table 2.1 (read 2026-08-27)
ASME/ANSI B36.10/19 - carbon, alloy and stainless steel pipe dimensions - Engineering ToolBox, edition not stated (read 2026-08-27)
Dimensions of steel and stainless steel pipes, ASME B36.10 and ASME B36.19 - Wermac, edition not stated (read 2026-08-27)
ANSI / ASME B36.10M pipe dimensions chart - Ferrobend, edition not stated (read 2026-08-27)
Nominal Pipe Size - Wikipedia, revision read 2026-08-27 (read 2026-08-27)