How is pipe wall thickness calculated?

Wall thickness equals (outside diameter minus inside diameter) divided by 2. This is a geometric relationship, not a pressure design calculation.

What is the wall thickness of Schedule 40 pipe?

It depends on nominal pipe size. For example, 1/2 inch NPS Schedule 40 has a wall thickness of 0.109 inches, while 4 inch NPS Schedule 40 has a wall thickness of 0.237 inches. Schedule 40 is not one universal thickness value.

What is the wall thickness of Schedule 80 pipe?

It also depends on nominal pipe size. For example, 1/2 inch NPS Schedule 80 has a wall thickness of 0.147 inches, while 4 inch NPS Schedule 80 has a wall thickness of 0.337 inches.

What is the difference between Schedule 40 and Schedule 80?

At the same nominal pipe size, Schedule 80 has a thicker wall, smaller inside diameter, and more material weight than Schedule 40, since the outside diameter stays the same but wall thickness increases.

Does Schedule 40 mean 0.040 inch wall thickness?

No. Schedule is a standardized designation, not a direct thickness reading. Schedule 40 wall thickness varies by pipe size, ranging from about 0.068 inches at 1/8 inch NPS to over 0.4 inches at larger sizes.

What is the wall thickness of 1/2 inch Schedule 40 pipe?

0.109 inches, with an outside diameter of 0.840 inches and an inside diameter of approximately 0.622 inches.

What is the wall thickness of 2 inch Schedule 40 pipe?

0.154 inches, with an outside diameter of 2.375 inches and an inside diameter of approximately 2.067 inches.

NPS stands for Nominal Pipe Size, a standardized designation system. NPS is not the same as the measured outside diameter, especially for smaller pipe sizes.

What does pipe schedule mean?

Schedule identifies a standardized wall thickness series that must be read together with nominal pipe size, since the actual thickness for a given schedule differs across different pipe sizes.

How do I measure pipe wall thickness?

For an open pipe end, measure OD and ID with a caliper and calculate thickness as (OD minus ID) divided by 2. For installed or closed piping, an ultrasonic thickness gauge is commonly used.

What is the difference between nominal and minimum wall thickness?

Nominal wall thickness is the standardized dimension listed in the applicable specification table. Minimum wall thickness is the minimum permissible thickness allowed after manufacturing tolerance, which can be somewhat less than the nominal value.

Does thicker pipe wall always mean higher pressure capacity?

Not necessarily. Pressure capability depends on material properties, design temperature, design code, joint efficiency, corrosion allowance and manufacturing tolerance in addition to nominal wall thickness.

Construction Charts

Pipe Wall Thickness Chart – Schedule 40, 80, 160 & Material Comparison

Q: What is pipe wall thickness?

Pipe wall thickness is the thickness of the pipe material between its outside diameter and inside diameter, calculated as (OD minus ID) divided by 2.

August 15, 2026

0 9 16 minutes read

Pipe Wall Thickness Chart - Schedule 40, 80, 160 & Material Comparison — Pipe Wall Thickness Chart

Pipe Wall Thickness Chart: Schedule 40, 80, 160 & Sizes | ConcreteCalculate.com

Pipe Schedule & Wall Thickness Reference

Pipe Wall Thickness Chart
Schedule 40, 80, 160 & Material Comparison

Schedule is a standardized wall thickness series, not a direct thickness value. This chart separates steel, stainless steel and PVC schedules by their actual governing standard.

ASME B36.10 SteelASME B36.19 StainlessASTM D1785 PVCNPS vs Actual ODUpdated August 2026

Reviewed by Muhammad Ramzan Babar, PhD Researcher & Calculator Developer · View Profile

🚫

Schedule 40 does not mean 0.040 inches

Schedule is a standardized dimension series that must be read together with nominal pipe size (NPS). The same schedule number produces a different wall thickness at every different pipe size. Never assume a schedule number converts directly into a thickness value.

⭐⭐⭐ Pipe Wall Thickness: Quick Reference

Values follow ASME B36.10 for carbon and alloy steel pipe, the primary steel pipe dimensional standard.

NPS	Outside Diameter	Schedule 40 Wall	Schedule 40 ID	Material/Standard
1/2	0.840 in	0.109 in	0.622 in	Carbon/alloy steel (ASME B36.10)
3/4	1.050 in	0.113 in	0.824 in	Carbon/alloy steel (ASME B36.10)
1	1.315 in	0.133 in	1.049 in	Carbon/alloy steel (ASME B36.10)
1-1/4	1.660 in	0.140 in	1.380 in	Carbon/alloy steel (ASME B36.10)
1-1/2	1.900 in	0.145 in	1.610 in	Carbon/alloy steel (ASME B36.10)
2	2.375 in	0.154 in	2.067 in	Carbon/alloy steel (ASME B36.10)
2-1/2	2.875 in	0.203 in	2.469 in	Carbon/alloy steel (ASME B36.10)
3	3.500 in	0.216 in	3.068 in	Carbon/alloy steel (ASME B36.10)
4	4.500 in	0.237 in	4.026 in	Carbon/alloy steel (ASME B36.10)

📌

Standards basis

ASME B36.10 contains standardized dimensions for welded and seamless wrought carbon and alloy steel pipe, including the schedule-based wall thickness system used throughout this quick reference. Full schedule tables appear in dedicated sections below.

⭐ What Is Pipe Wall Thickness?

Wall thickness is the pipe material’s thickness between its outer and inner surfaces.

Outside diameter (OD)

The measured external diameter of the pipe.

Inside diameter (ID)

The internal flow diameter, the open space through which fluid or gas travels.

Wall thickness

The material thickness between OD and ID, calculated as (OD minus ID) divided by 2.

Why it matters

Wall thickness affects strength, weight, flow area, and (as one factor among several) pressure handling capability.

⭐⭐⭐ NPS vs Actual Outside Diameter

NPS is a standardized nominal designation, not a direct outside diameter measurement.

🚫

NPS is not the same as measured OD

NPS 12 and smaller have outside diameters that are numerically larger than their corresponding nominal size label. For example, 1/2 inch NPS has an actual OD of 0.840 inches, not 0.500 inches. NPS 14 and larger have an actual OD that matches the nominal size in inches.

NPS	Actual OD (in)	Actual OD (mm)
1/2	0.840	21.34
3/4	1.050	26.67
1	1.315	33.40
1-1/4	1.660	42.16
1-1/2	1.900	48.26
2	2.375	60.33
3	3.500	88.90
4	4.500	114.30
6	6.625	168.28
8	8.625	219.08
10	10.750	273.05
12	12.750	323.85
14	14.000	355.60
16	16.000	406.40

⭐⭐⭐ What Is Pipe Schedule?

Schedule identifies a standardized wall thickness series, but the actual thickness value depends entirely on the pipe size it is paired with.

📐

Schedule must be read together with NPS

2 inch Schedule 40 does not have the same wall thickness as 4 inch Schedule 40. At 2 inch NPS, Schedule 40 wall thickness is 0.154 inches; at 4 inch NPS, Schedule 40 wall thickness is 0.237 inches. The schedule number identifies a position within a standardized thickness series, not a fixed universal value.

Schedule	Applicable Standard	Material
5, 5S	ASME B36.10 (5) / B36.19 (5S)	Steel / Stainless
10, 10S	ASME B36.10 / B36.19	Steel / Stainless
20, 30	ASME B36.10	Steel
40, 40S	ASME B36.10 / B36.19	Steel / Stainless
60	ASME B36.10	Steel
80, 80S	ASME B36.10 / B36.19	Steel / Stainless
100, 120, 140, 160	ASME B36.10	Steel
STD, XS, XXS	ASME B36.10	Steel

🚫

Steel and stainless steel schedules are separate systems

Steel pipe schedules follow ASME B36.10. Stainless steel pipe schedules follow ASME B36.19, using S designations. Some B36.19 wall thicknesses differ from the equivalent B36.10 schedule at certain sizes, so these tables should never be treated as identical.

⭐⭐⭐ Steel Pipe: Schedule 40, 80 & 160 (ASME B36.10)

The primary carbon and alloy steel pipe dimensional reference.

NPS	OD (in)	Sch 40 Wall	Sch 40 ID	Sch 80 Wall	Sch 80 ID
1/2	0.840	0.109	0.622	0.147	0.546
3/4	1.050	0.113	0.824	0.154	0.742
1	1.315	0.133	1.049	0.179	0.957
1-1/4	1.660	0.140	1.380	0.191	1.278
1-1/2	1.900	0.145	1.610	0.200	1.500
2	2.375	0.154	2.067	0.218	1.939
3	3.500	0.216	3.068	0.300	2.900
4	4.500	0.237	4.026	0.337	3.826
5	5.563	0.258	5.047	0.375	4.813
6	6.625	0.280	6.065	0.432	5.761
8	8.625	0.322	7.981	0.500	7.625
10	10.750	0.365	10.020	0.593	9.564
12	12.750	0.406	11.938	0.687	11.376

NPS	OD (in)	Sch 160 Wall	Sch 160 ID
1/2	0.840	0.187	0.466
1	1.315	0.250	0.815
2	2.375	0.344	1.687
4	4.500	0.531	3.438
6	6.625	0.719	5.187
8	8.625	0.906	6.813

⭐

Schedule 40 vs Schedule 80 comparison

At the same NPS, Schedule 80 always uses more wall thickness, resulting in a smaller inside diameter, less flow area, and more material weight than Schedule 40. Schedule 160 continues that pattern with an even heavier wall and smaller bore.

⭐ STD, XS & XXS Pipe Wall Designations

These are alternative wall designations within ASME B36.10, not simply additional schedule numbers.

STD (Standard Weight)

For NPS 1/8 through 10, STD wall thickness matches Schedule 40. For NPS 12 and larger, STD uses a different (thinner relative) wall than Schedule 40 at that size, since Schedule 40’s thickness increases faster than STD at larger diameters.

XS (Extra Strong)

For NPS 1/8 through 8, XS wall thickness matches Schedule 80. For NPS 10 and larger, XS diverges from Schedule 80 and uses its own fixed wall thickness value.

XXS (Double Extra Strong)

A significantly heavier wall designation available only for a limited range of smaller to mid NPS sizes; it should not be treated as a universal “thicker version” available at every size, since XXS is not offered across the full NPS range.

NPS	OD (in)	STD Wall	XS Wall	XXS Wall
1/2	0.840	0.109	0.147	0.294
1	1.315	0.133	0.179	0.358
2	2.375	0.154	0.218	0.436
4	4.500	0.237	0.337	0.674
6	6.625	0.280	0.432	0.864
8	8.625	0.322	0.500	0.875
12	12.750	0.375	0.500	—

Notice XXS is not available beyond a limited size range in this common reference; always confirm actual availability for the specific NPS against the current ASME B36.10 table before specifying.

⭐⭐⭐ Stainless Steel Pipe: ASME B36.19

ASME B36.19 covers welded and seamless wrought stainless steel pipe using S schedule designations, kept as a separate table from carbon/alloy steel B36.10.

NPS	OD (in)	Sch 10S Wall	Sch 40S Wall	Sch 80S Wall
1/8	0.405	0.049	0.068	0.095
1/4	0.540	0.065	0.088	0.119
3/8	0.675	0.065	0.091	0.126
1/2	0.840	0.083	0.109	0.147
3/4	1.050	0.083	0.113	0.154
1	1.315	0.109	0.133	0.179
2	2.375	0.109	0.154	0.218
4	4.500	0.120	0.237	0.337
6	6.625	0.134	0.280	0.432
8	8.625	0.148	0.322	0.500

📌

40S and 80S generally align with 40 and 80

40S wall thickness matches Schedule 40 for NPS 1/8 through NPS 12, and 80S wall thickness matches Schedule 80 for NPS 1/8 through NPS 8. Beyond those ranges, and for certain 10S sizes, B36.19 values can differ from the equivalent B36.10 numbers, so always verify the specific size against the current standard.

⭐⭐⭐ ASME B36.10 vs B36.19

These are related but distinct standards, and their dimensions are not universally identical.

Feature	ASME B36.10	ASME B36.19
Covers	Welded and seamless wrought carbon/alloy steel pipe	Welded and seamless wrought stainless steel pipe
Schedule labels	5, 10, 20, 30, 40, 60, 80, 100, 120, 140, 160, STD, XS, XXS	5S, 10S, 40S, 80S
Dimensional overlap	Baseline reference for most steel schedules	Generally matches B36.10 within stated size ranges, with noted exceptions

⚠️

Not universally identical

ASME’s own documentation notes that wall thicknesses for certain sizes, including some Schedule 10S, 40S and 80S combinations at larger NPS, differ from the equivalent ANSI/ASME B36.10 values. Always confirm which standard applies to the actual material being specified, rather than assuming carbon steel and stainless steel dimensions are interchangeable at the same nominal schedule label.

⭐⭐⭐ PVC Pipe Wall Thickness: ASTM D1785

PVC pipe uses an entirely separate dimensional standard from steel; never mix these values into a steel schedule table.

NPS	OD (in)	Sch 40 Min. Wall	Sch 80 Min. Wall	Sch 120 Min. Wall
1/8	0.405	0.068	0.095	—
1/4	0.540	0.088	0.119	—
1/2	0.840	0.109	0.147	0.170
3/4	1.050	0.113	0.154	0.203
1	1.315	0.133	0.179	0.230
2	2.375	0.154	0.218	0.318
4	4.500	0.237	0.337	0.437

📌

Standards basis and important coincidence

ASTM D1785 covers PVC Schedule 40, 80 and 120 pipe. Notice that PVC Schedule 40 and 80 wall thickness values happen to match the equivalent ASME B36.10 steel values at many common sizes, since PVC schedule dimensions were originally designed to align with steel pipe OD and schedule conventions, but the two standards remain governed separately and should be cited to their correct source.

CPVC pipe

Covered by ASTM F441, with dimensions that can differ from PVC despite sharing nominal size and schedule labels; always use the CPVC-specific table rather than assuming PVC dimensions apply.

ABS pipe

Uses its own applicable ASTM standard, such as ASTM D2661 for certain ABS Schedule 40 DWV pipe; do not mix ABS dimensions with PVC or steel schedule tables.

PVC Schedule 40 vs Schedule 80 pipe comparison showing wall thickness differences

⭐⭐⭐ Pipe Material vs Dimensional Standard

Using the wrong standard for a given material is one of the most common and consequential pipe sizing errors.

Material	Typical Dimension Standard
Carbon/alloy steel	ASME B36.10
Stainless steel	ASME B36.19
PVC	ASTM D1785
CPVC	ASTM F441
ABS	Applicable ASTM standard (varies by product, e.g. ASTM D2661 for some DWV pipe)
Copper tube	Type K/L/M systems (separate from NPS steel schedules)

🚫

Copper tube uses a completely different sizing system

Copper tube is sized and thickness-rated using Type K, L, and M designations, which are entirely separate from NPS steel pipe schedules. Never apply a steel pipe schedule chart to copper tube.

⭐⭐⭐ Pipe Wall Thickness Calculation Formulas

These are geometric relationships, not pressure design equations.

To Find	Formula
Wall thickness	t = (OD − ID) / 2
Inside diameter	ID = OD − 2t
Outside diameter	OD = ID + 2t

🧮

Worked calculation

For a pipe with OD = 2.375 inches and ID = 2.067 inches: t = (2.375 minus 2.067) divided by 2 = 0.154 inches, matching the standard 2 inch NPS Schedule 40 value.

⭐⭐⭐ Pipe Wall Thickness and Pressure

Wall thickness is one input into pressure capability, not the sole determining factor.

🚫

Does a thicker pipe always handle more pressure? Not necessarily.

Pressure capability depends on the applicable design code, material properties, design temperature, design pressure, weld or joint efficiency, corrosion allowance, and manufacturing tolerance, in addition to nominal wall thickness. Do not select a schedule based on wall thickness alone without completing the applicable pressure design calculation for the actual service conditions.

Design code requirements

Pressure piping design typically follows an applicable code (such as ASME B31 series piping codes) that defines the required calculation method, not simply a schedule lookup.

Corrosion allowance ⭐⭐⭐

Design thickness commonly includes an added corrosion allowance beyond the structurally required minimum, so that the pipe retains adequate strength as material is gradually lost to corrosion over its service life. Nominal wall thickness minus corrosion allowance approximates the structurally required design thickness.

⭐⭐⭐ Nominal vs Minimum Wall Thickness

These are related but distinct values that should never be treated as interchangeable.

Term	Definition
Nominal wall thickness	The standardized dimension listed in the applicable specification table (such as the Schedule 40 value)
Minimum wall thickness	The minimum permissible thickness allowed under the applicable specification’s manufacturing tolerance, which can be somewhat less than nominal

📏

Manufacturing tolerance explains the gap

Actual measured wall thickness on a real pipe can differ from the nominal value due to normal manufacturing tolerance; this is why specifications define a minimum permissible thickness rather than requiring every point to measure exactly the nominal value.

⭐⭐⭐ Measuring Pipe Wall Thickness

Different situations call for different measurement tools.

Open pipe end

Measure OD and ID directly with a caliper, then calculate t = (OD minus ID) / 2.

Micrometer

Provides higher precision measurement than a standard caliper for critical verification work.

Ultrasonic thickness gauge ⭐⭐

Used for installed or closed piping where the wall cannot be measured directly with a caliper. A probe is coupled to the surface, calibrated for the specific material’s sound velocity, and used to measure thickness non-destructively. Surface condition, coating, and material properties all affect measurement accuracy.

Destructive cross-section

Cutting a sample for direct measurement, used in specific inspection or testing scenarios rather than routine field checks.

Inspection considerations ⭐⭐

Corrosion, erosion, pitting, and local thinning can all reduce measured wall thickness below the original nominal or minimum value at specific locations, particularly near welds or flow disturbances.

Pipe wall thickness loss

Thickness loss equals original or reference thickness minus current measured thickness. Evaluating whether remaining thickness is acceptable requires the applicable engineering or code criteria for that specific system, not a generic rule.

Pipe Wall Thickness, Flow Area & Weight

Changing schedule at a fixed NPS changes ID, which changes flow area and material weight.

Flow area

Internal flow area follows A = πD²/4 using the actual inside diameter. A thicker wall reduces ID and therefore reduces available flow area at the same nominal pipe size.

Weight

Greater wall thickness generally means more material per unit length, and therefore more weight per unit length, at the same OD and material. See the Pipe Weight Calculator for weight calculations by size and schedule.

NPS 2 Schedule	ID (in)	Flow Area (in²)
Schedule 40	2.067	3.36
Schedule 80	1.939	2.95
Schedule 160	1.687	2.24

⭐⭐⭐ Pipe Wall Thickness by Common NPS

Quick reference across the most frequently searched sizes.

1/2 inch pipe ⭐

OD 0.840 in. Sch 40: 0.109 in wall, 0.622 in ID. Sch 80: 0.147 in wall, 0.546 in ID. Sch 160: 0.187 in wall, 0.466 in ID.

3/4 inch pipe

OD 1.050 in. Sch 40: 0.113 in wall, 0.824 in ID. Sch 80: 0.154 in wall, 0.742 in ID.

1 inch pipe

OD 1.315 in. Sch 40: 0.133 in wall, 1.049 in ID. Sch 80: 0.179 in wall, 0.957 in ID. Sch 160: 0.250 in wall, 0.815 in ID.

2 inch pipe ⭐

OD 2.375 in. Sch 40: 0.154 in wall, 2.067 in ID. Sch 80: 0.218 in wall, 1.939 in ID. Sch 160: 0.344 in wall, 1.687 in ID.

4 inch pipe ⭐

OD 4.500 in. Sch 40: 0.237 in wall, 4.026 in ID. Sch 80: 0.337 in wall, 3.826 in ID. Sch 160: 0.531 in wall, 3.438 in ID.

6 inch pipe

OD 6.625 in. Sch 40: 0.280 in wall, 6.065 in ID. Sch 80: 0.432 in wall, 5.761 in ID.

8 inch pipe

OD 8.625 in. Sch 40: 0.322 in wall, 7.981 in ID. Sch 80: 0.500 in wall, 7.625 in ID.

12 inch pipe

OD 12.750 in. Sch 40: 0.406 in wall, 11.938 in ID. Sch 80: 0.687 in wall, 11.376 in ID.

⭐ Pipe Wall Thickness Applications

Different applications call for different materials, standards, and schedule considerations.

Plumbing

Steel, PVC, CPVC, and copper each have their own dimensional standard; never mix schedule assumptions across materials.

Water lines

Material, schedule, nominal size, pressure requirements, temperature, and the applicable plumbing code together determine correct selection.

Industrial piping

Pressure, temperature, material, corrosion allowance, design code, and inspection requirements govern selection far beyond a simple schedule lookup.

Structural applications

Round HSS and structural pipe may use different dimensional and specification systems than pressure piping schedules; do not use a generic pipe schedule chart for structural design without confirming the applicable structural specification.

Construction ⭐

Water lines, pump systems, compressed air, concrete equipment, drainage, and temporary piping on construction sites commonly use steel or PVC schedule pipe; confirm material and standard before ordering fittings or replacement sections.

⭐⭐⭐ Pipe Wall Thickness Visual Guide

Original diagrams explaining pipe cross-section, schedule comparison, and NPS versus actual OD.

Pipe cross-section: outside diameter (OD), wall thickness, inside diameter (ID), and centerline.

Same NPS, increasing schedule number: wall thickness increases while ID (bore) decreases.

1/2 inch NPS does not measure 0.500 inches; its actual outside diameter is approximately 0.840 inches.

⭐⭐⭐ Pipe Wall Thickness Worked Examples

These examples demonstrate the core geometric relationships and schedule comparisons.

1. Calculate Wall Thickness

Given: OD = 2.375 in, ID = 2.067 in.Result: t = (2.375 minus 2.067) / 2 = 0.154 in, matching 2 inch NPS Schedule 40.

2. Calculate ID

Given: OD = 2.375 in, wall = 0.154 in.Result: ID = 2.375 minus 2(0.154) = 2.067 in.

3. Schedule 40 vs Schedule 80

Given: 4 inch NPS in both schedules.Result: Sch 40 has 0.237 in wall and 4.026 in ID; Sch 80 has 0.337 in wall and 3.826 in ID. Same OD (4.500 in), different wall and bore.

4. Convert Thickness to mm

Given: 0.154 in.Result: 0.154 x 25.4 = 3.91 mm.

5. Stainless vs Carbon Steel

Given: 4 inch NPS Schedule 40 in both B36.10 carbon steel and B36.19 stainless steel (40S).Result: both commonly show 0.237 in wall at this size, but always verify the specific size against the current standard, since some larger sizes and certain schedules differ between B36.10 and B36.19.

⭐⭐⭐ Common Pipe Wall Thickness Mistakes

Most pipe sizing errors trace back to one of these misunderstandings.

❌ Assuming NPS equals OD

Nominal pipe size and actual outside diameter are different values for NPS 12 and smaller.

❌ Assuming Schedule 40 means 0.040 inches

Schedule is a series designation, not a direct decimal thickness value.

❌ Assuming same schedule means same thickness at every size

Schedule 40 wall thickness varies significantly across different NPS values.

❌ Mixing steel and stainless schedules

B36.10 and B36.19 are related but not universally identical.

❌ Mixing PVC and steel tables

PVC follows ASTM D1785, a separate standard from ASME B36.10.

❌ Confusing nominal and minimum thickness

Manufacturing tolerance means actual measured thickness can be less than nominal.

❌ Ignoring manufacturing tolerance

Real pipe thickness varies within the specification’s allowed tolerance band.

❌ Using wall thickness alone for pressure design

Pressure capability depends on material, code, temperature, and other factors together.

❌ Assuming thicker wall always means higher pressure

Not necessarily true without the complete applicable design calculation.

❌ Ignoring corrosion allowance

Design thickness commonly includes an added allowance beyond structural minimum.

❌ Confusing pipe with tube

Pipe uses nominal sizing; tube is sized directly by actual outside diameter.

❌ Using a generic schedule chart for structural HSS

Structural round HSS may use a different specification system than pressure piping schedules.

Frequently Asked Questions

The thickness of pipe material between OD and ID, calculated as (OD minus ID) divided by 2.

t = (OD minus ID) / 2, a geometric relationship rather than a pressure design formula.

It depends on NPS; for example, 0.109 inches at 1/2 inch NPS and 0.237 inches at 4 inch NPS.

Also depends on NPS; for example, 0.147 inches at 1/2 inch NPS and 0.337 inches at 4 inch NPS.

At the same NPS, Schedule 80 has a thicker wall, smaller ID, and more weight than Schedule 40, with the same OD.

No, schedule is a designation, not a direct thickness reading; the actual value varies by pipe size.

0.109 inches, with a 0.840 inch OD and approximately 0.622 inch ID.

0.154 inches, with a 2.375 inch OD and approximately 2.067 inch ID.

Nominal Pipe Size, a standardized designation that is not the same as the measured outside diameter.

NPS 12 and smaller have an actual OD larger than the nominal number; for example, 1/2 inch NPS measures 0.840 inches.

A standardized wall thickness series that must be read together with NPS, since actual thickness differs by size.

Measure OD and ID with a caliper for an open pipe and calculate t = (OD minus ID) / 2, or use an ultrasonic thickness gauge for installed piping.

Nominal is the standardized listed dimension; minimum is the lowest permissible thickness allowed under manufacturing tolerance.

Not necessarily; pressure capability depends on material, code, temperature, joint efficiency, and corrosion allowance together.

B36.10 covers carbon and alloy steel pipe; B36.19 covers stainless steel pipe using S schedules, with some dimensions differing between the two at certain sizes.

📄 Download Pipe Wall Thickness Chart PDF

This PDF is designed as a genuine field engineering reference. Use the print button to create a print-ready or downloadable version.

NPS, OD, schedule, wall, ID tableSchedule 40 chartSchedule 80 chartSchedule 160 chartSTD, XS, XXS chartStainless 10S/40S/80S chartPVC Schedule 40/80/120 chartInches and millimetersCalculation formulasMeasurement guideSchedule comparisonWorked examples

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Pipe Wall Thickness ChartSchedule 40, 80, 160 & Material Comparison