ASTM D1785 / NSF 61 Schedule 40 True ID: 1.38" (35.05 mm) 370 PSI @ 73°F

1-1/4" Schedule 40 PVC Pipe Volume & Capacity Calculator

Standard 1-1/4" nominal Schedule 40 PVC pipe has an exact inside diameter of 1.38 inches, holding 0.0777 US gallons (0.965 liters per meter) per linear foot. Part of our PVC Pipe Volume Hub and universal Pipe Volume Calculator suite.

Presets:

Calculated Result

Total Liquid Capacity

Internal Holding Volume

1.554 US gallons

≈ 5.882 litres

Unit Conversions

US Gallons 1.554 gal

Litres 5.882 L

Cubic Feet (ft³) 0.2077 ft³

Cubic Inches (in³) 358.97 in³

Imperial Gallons 1.294 UK gal

Cubic Meters (m³) 0.0059 m³

Filled Water Weight 13.0 lbs (5.9 kg)

Linear Capacity Rate 0.0777 gal/ft

Calculations are based on cylindrical formula $V = \pi r^2 L$. Verify dimensions against manufacturer specs for code submittals.

Pre-Calculated Capacity Table

1-1/4" Schedule 40 PVC Quick Reference Sizing Chart

Instant capacity and weight lookup table for common pipe lengths filled with water at 60°F (15.5°C).

Pipe Length (Ft)	US Gallons	Liters	Cubic Feet (ft³)	Water Weight (lbs)	Dry Pipe (lbs)	Total Wet Weight
1 ft	0.078 gal	0.29 L	0.010 ft³	0.6 lbs	0.4 lbs	1.1 lbs
2 ft	0.155 gal	0.59 L	0.021 ft³	1.3 lbs	0.9 lbs	2.2 lbs
5 ft	0.389 gal	1.47 L	0.052 ft³	3.2 lbs	2.1 lbs	5.4 lbs
10 ft	0.777 gal	2.94 L	0.104 ft³	6.5 lbs	4.3 lbs	10.8 lbs
20 ft	1.554 gal	5.88 L	0.208 ft³	13.0 lbs	8.6 lbs	21.5 lbs
50 ft	3.89 gal	14.7 L	0.52 ft³	32.4 lbs	21.4 lbs	53.8 lbs
100 ft	7.77 gal	29.4 L	1.04 ft³	64.8 lbs	42.8 lbs	107.6 lbs
250 ft	19.43 gal	73.5 L	2.60 ft³	162.0 lbs	107.0 lbs	269.0 lbs
500 ft	38.85 gal	147.1 L	5.20 ft³	324.0 lbs	214.0 lbs	538.0 lbs

Engineering Formula

How to Calculate 1-1/4" PVC Pipe Volume Manually

Step-by-step mathematical demonstration using cylinder geometric principles and ASTM D1785 specifications.

Step 1

Determine the Internal Radius (r)

Nominal size is 1-1/4", but true inner diameter is 1.38 inches.

r = ID / 2 = 1.38 / 2 = 0.6900"

Step 2

Calculate Cross-Sectional Area (A)

Compute circular cross-section area using $A = \pi \times r^2$:

A = \pi \times (0.6900)^2 = 1.4957 sq in

Step 3

Calculate Linear Foot Volume

Multiply cross-sectional area by 12 inches (1 linear foot):

V_linear = 1.4957 \times 12 = 17.949 cu in/ft

Step 4

Convert to US Gallons & Liters

Divide cubic inches by 231 (cubic inches in 1 US Gallon):

Gallons/Ft = 17.949 / 231 = 0.0777 Gal/Ft

Technical Specifications

1-1/4" Schedule 40 PVC Engineering Profile

Physical dimensions, pressure thresholds, and hydraulic velocity limits.

Outside Diameter (OD)

1.66 inches

42.2 mm

Inside Diameter (ID)
1.38 inches
35.05 mm

Wall Thickness

0.14 inches

ASTM D1785 Tolerance

Max Recommended Flow

23.3 GPM

At 5 ft/s velocity

Working Pressure

370 PSI

At 73°F (23°C)

Max Temperature Limit

140°F

60°C continuous

Common Plumbing & Piping Applications for 1-1/4" Schedule 40:

Sump pump discharge lines
Well pump drop pipe lines
Commercial pool plumbing feeds

Primary Use Case: Frequently utilized in sump basin discharge systems, pressure well installations, and secondary booster pump loops.

Size Navigation

Compare Other PVC Pipe Sizes

Explore adjacent diameter calculations or compare with different pressure schedules.

← Previous Size 1" Schedule 40 PVC Overview Directory All PVC Pipe Sizes (Sch 40 & 80) Next Size → 1-1/2" Schedule 40 PVC Compare Alternative Schedule ↔ 1-1/4" Schedule 80 PVC

Cross-Material Comparison

Compare 1-1/4" Pipe in Other Materials

Compare fluid holding capacity, wall thickness, and weight against other standard piping materials for 1-1/4" nominal diameter:

Copper Tubing (ASTM B88) 1-1/4" Copper (Type K/L/M) Cast Iron DWV (ASTM A888) Cast Iron Soil Pipe Schedule 40 Steel (ASTM A53) Steel Schedule 40 Pipe Fluid Velocity & GPM 1-1/4" Flow Rate Calculator

Expert FAQ Guide

1-1/4" Schedule 40 PVC FAQs

Frequently asked engineering and volumetric capacity questions for 1-1/4" PVC.

2 Questions Answered

Q1 How many gallons in 50 feet of 1-1/4" Schedule 40 PVC pipe?

A 50-foot run of 1-1/4" Schedule 40 PVC pipe holds approximately 3.89 US Gallons (14.71 Liters) of water.

Q2 What is the inner diameter of 1-1/4 inch Schedule 40 PVC?

The true inside diameter is 1.380 inches (35.05 mm) with an outer diameter of 1.660 inches.

Total Liquid Capacity

Unit Conversions

1-1/4" Schedule 40 PVC Quick Reference Sizing Chart

How to Calculate 1-1/4" PVC Pipe Volume Manually

Determine the Internal Radius (r)

Calculate Cross-Sectional Area (A)

Calculate Linear Foot Volume

Convert to US Gallons & Liters

1-1/4" Schedule 40 PVC Engineering Profile

Common Plumbing & Piping Applications for 1-1/4" Schedule 40:

Compare Other PVC Pipe Sizes

Compare 1-1/4" Pipe in Other Materials

1-1/4" Schedule 40 PVC FAQs

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