Pipe Schedule 40/80 Chart

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Filter by size or series; the chart covers only the verified entries listed here.

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Reference chart
NPS	Schedule	OD (in)	Wall (in)	Calculated ID (in)	OD (mm)	Wall (mm)	Calculated ID (mm)
1/2	40	0.84	0.109	0.622	21.336	2.7686	15.7988
1/2	80	0.84	0.147	0.546	21.336	3.7338	13.8684
3/4	40	1.05	0.113	0.824	26.67	2.8702	20.9296
3/4	80	1.05	0.154	0.742	26.67	3.9116	18.8468
1	40	1.315	0.133	1.049	33.401	3.3782	26.6446
1	80	1.315	0.179	0.957	33.401	4.5466	24.3078
1-1/4	40	1.66	0.14	1.38	42.164	3.556	35.052
1-1/4	80	1.66	0.191	1.278	42.164	4.8514	32.4612
1-1/2	40	1.9	0.145	1.61	48.26	3.683	40.894
1-1/2	80	1.9	0.2	1.5	48.26	5.08	38.1
2	40	2.375	0.154	2.067	60.325	3.9116	52.5018
2	80	2.375	0.218	1.939	60.325	5.5372	49.2506
2-1/2	40	2.875	0.203	2.469	73.025	5.1562	62.7126
2-1/2	80	2.875	0.276	2.323	73.025	7.0104	59.0042
3	40	3.5	0.216	3.068	88.9	5.4864	77.9272
3	80	3.5	0.3	2.9	88.9	7.62	73.66
3-1/2	40	4.0	0.226	3.548	101.6	5.7404	90.1192
3-1/2	80	4.0	0.318	3.364	101.6	8.0772	85.4456
4	40	4.5	0.237	4.026	114.3	6.0198	102.2604
4	80	4.5	0.337	3.826	114.3	8.5598	97.1804
5	40	5.563	0.258	5.047	141.3002	6.5532	128.1938
5	80	5.563	0.375	4.813	141.3002	9.525	122.2502
6	40	6.625	0.28	6.065	168.275	7.112	154.051
6	80	6.625	0.432	5.761	168.275	10.9728	146.3294
8	40	8.625	0.322	7.981	219.075	8.1788	202.7174
8	80	8.625	0.5	7.625	219.075	12.7	193.675

Formula and method

Nominal ID = OD − 2t; millimetres = inches × 25.4. NPS is a designation, not OD or ID; Schedule is not a pressure rating.

Worked example

NPS 2, Sch40: OD 2.375 in, wall 0.154 in, calculated ID 2.067 in = 52.5018 mm. Sch80 keeps the 2.375 in OD but increases the wall to 0.218 in, reducing ID to 1.939 in.

Assumptions and limits

Coverage is steel pipe Sch40/80 at NPS 1/2, 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3, 3-1/2, 4, 5, 6 and 8. Missing sizes are not extrapolated.
These are mathematical conversions of nominal inch dimensions; extra decimals do not imply manufacturing precision. Rounded manufacturer metric dimensions may differ slightly. Allow for manufacturing tolerance, corrosion and lining.
Geometry reference only: no allowable working pressure, temperature class or compliance conclusion is provided. Check material, joints and design code separately. Do not substitute PVC/CPVC, copper or stainless S schedules.
STD and XS are not synonyms for Sch40 and Sch80 across all sizes; this chart does not extend above NPS 8.

Frequently asked questions

Is NPS 2 exactly 2 inches OD?

No. NPS 2 is a designation; its listed OD is 2.375 in. Sch40 and Sch80 at the same NPS share OD but differ in wall and ID.

Why is ID calculated rather than copied?

Some public tables contain rounding or print inconsistencies in ID or metric columns. This tool uses verified inch OD/wall and ID=OD−2t to preserve the geometric relationship, with nominal rather than measured values.

Can this select a pressure class or pump?

No. Dimensions are inputs only. Pressure design also needs material, temperature, joints and code; pump calculations need the actual bore, flow, losses and manufacturer curves.

References

Pipe Schedule 40/80 Chart practical guide and common questions

What does Pipe Schedule 40/80 Chart calculate?

Choose the NPS designation and Schedule. Nominal inch OD and wall come from manufacturer literature; ID is calculated as OD−2t and millimetres use 25.4 per inch. Coverage is limited to the 13 listed sizes, not a complete ASME standard or a measured bore. Nominal ID = OD − 2t; millimetres = inches × 25.4. NPS is a designation, not OD or ID; Schedule is not a pressure rating.

When is this useful?

NPS 2, Sch40: OD 2.375 in, wall 0.154 in, calculated ID 2.067 in = 52.5018 mm. Sch80 keeps the 2.375 in OD but increases the wall to 0.218 in, reducing ID to 1.939 in.

How do I enter the inputs?

Enter the inputs for Pipe Schedule 40/80 Chart: Nominal pipe size (NPS), Schedule. Calculate, check the units and assumptions, then copy or download the results.

How should I interpret the results?

Coverage is steel pipe Sch40/80 at NPS 1/2, 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3, 3-1/2, 4, 5, 6 and 8. Missing sizes are not extrapolated. These are mathematical conversions of nominal inch dimensions; extra decimals do not imply manufacturing precision. Rounded manufacturer metric dimensions may differ slightly. Allow for manufacturing tolerance, corrosion and lining. Geometry reference only: no allowable working pressure, temperature class or compliance conclusion is provided. Check material, joints and design code separately. Do not substitute PVC/CPVC, copper or stainless S schedules. STD and XS are not synonyms for Sch40 and Sch80 across all sizes; this chart does not extend above NPS 8.

Where are my inputs processed?

Pipe Schedule 40/80 Chart runs in this browser. Inputs are not uploaded to a calculation server; copying and CSV download require your action. The existing site analytics and advertising still load.