About

Engineers and pipefitters use this tool to determine the precise volume of fluid a pipe section can hold. This data is critical for calculating structural loads (weight of water), determining the amount of chemical additives required for system dosing, or estimating priming volumes for pumps. Unlike simple cylinder calculators, this tool incorporates the ANSI/ASME B36.10M standards for Schedule 40 and Schedule 80 pipes, where the Inner Diameter (ID) differs significantly from the Nominal Pipe Size (NPS). For example, a 2-inch Sch 80 pipe has a thicker wall and holds less volume than a Sch 40 pipe.

Formulas

The volume V is derived from the cylindrical volume formula using the pipe's internal radius r and length L.

V = π × r² × L

To find the weight of water W:

W = V_gal × 8.34 lbs/gal

Note: r is ID2, where ID is looked up from the Schedule table, not the Nominal Size.

Reference Data

Nominal Size	OD (inches)	Sch 40 ID (inches)	Sch 80 ID (inches)	Gal/100ft (Sch 40)
1/2"	0.840	0.622	0.546	1.58
3/4"	1.050	0.824	0.742	2.77
1"	1.315	1.049	0.957	4.49
2"	2.375	2.067	1.939	17.41
3"	3.500	3.068	2.900	38.47
4"	4.500	4.026	3.826	66.13
6"	6.625	6.065	5.761	150.0
8"	8.625	7.981	7.625	259.9

Frequently Asked Questions

Nominal Pipe Size (NPS) refers to the outer diameter standard. As the Schedule (wall thickness) increases, the hole inside gets smaller, but the outside remains the same to fit standard fittings.

Schedule 80 has thicker walls to handle higher pressures. Consequently, it holds slightly less liquid volume than Schedule 40 pipe of the same nominal size.

No. This tool calculates the "wetted volume" (capacity) inside the pipe. It does not calculate the volume of steel or PVC used to make the pipe.