2 in schedule 40 pipe flow and volume calculator
2 in schedule 40 pipe has an outside diameter of 60.3 mm and a bore of 52.5 mm, a wall thickness of 3.90 mm. Nominal pipe size is a label, not a measurement — nothing about a 1-inch pipe is one inch.
Domestic water is usually kept between 1 and 2.4 m/s to limit noise and erosion.
Copper and plastic about 140; new steel 130; old steel 100.
- Flow in US gallons per minute
- 51.468
- Inside diameter
- 52.50
- Wall thickness
- 3.900
- Bore area
- 2164.75 mm2
- Water content per metre
- 2.1648
- Water in the run
- 54.12
- Weight of that water
- 54.12
- Friction head loss
- 1.190
- Pressure drop
- 11.671 kPa
Show the working
- Flow velocity = 1.5
- Pipe run = 25
- Hazen-Williams C = 140
- Fluid density = 1000
- Inside diameter = 52.5 = 52.5
- outside = 60.3 = 60.3
- Wall thickness = (60.3 - 52.5) / 2 = 3.9
- Bore area = pi * 52.5^2 / 4 = 2164.75
- area_m2 = 2164.75 / 1e6 = 0.002 164 75
- Water content per metre = 2164.75 / 1000 = 2.164 75
- Water in the run = 2.164 75 * 25 = 54.1188
- flow_m3s = 0.002 164 75 * 1.5 = 0.003 247 13
- Flow at that velocity = 0.003 247 13 * 60000 = 194.828
- Flow in US gallons per minute = 194.828 / 3.785411784 = 51.4681
- loss_per_m = 10.67 * (0.003 247 13)^1.852 / (140^1.852 * (52.5/1000)^4.87) = 0.047 605 5
- Friction head loss = 0.047 605 5 * 25 = 1.190 14
- Pressure drop = 1.190 14 * 1000 * g0 / 1000 = 11.6713
- Weight of that water = 54.1188 * 1000 / 1000 = 54.1188
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- bore area = pi d^2 / 4
- flow = area x velocity
- Hazen-Williams head loss per metre = 10.67 Q^1.852 / (C^1.852 d^4.87), SI units
Nominal pipe size is a legacy label. Above 14 inch NPS the outside diameter equals the nominal size; below it, neither dimension matches.
Hazen-Williams is an empirical formula fitted to water near room temperature. For other fluids or for gases, use Darcy-Weisbach.
Fittings add loss too. A rule of thumb is to add 30 to 50% to the straight-run figure for a typical domestic circuit.
2 in pipe at common velocities
| Velocity (m/s) | Flow (L/min) | Flow (US gpm) |
|---|---|---|
| 0.5 | 64.9 | 17.16 |
| 1 | 129.9 | 34.31 |
| 1.5 | 194.8 | 51.47 |
| 2 | 259.8 | 68.62 |
| 2.5 | 324.7 | 85.78 |
| 3 | 389.7 | 102.94 |
Frequently asked
What is the inside diameter of 2 in schedule 40 pipe?
52.5 mm, against an outside diameter of 60.3 mm.
How much water does 2 in pipe hold?
2.165 litres per metre of run.
Where the numbers come from
- Dimensions are the ASME B36.10 schedule 40 values for the nominal size.