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Hydraulic Hose Selection Calculator

Select the correct hydraulic hose dash size from flow rate, pressure, and velocity limits. Calculates pressure drop and fitting losses.

Inputs

Results

Recommended SAE dash size

8

Hose ID (inches)0.5
Minimum required ID (in)0.4
Actual velocity (ft/s)12.83
Total pressure drop (PSI)5.3
Reynolds number4,838
Pressure rating usage (%)75
Power loss (HP)0.03
Velocity LabelPressure (≤20 ft/s)
How to Use This Calculator
  1. Enter Flow rate (GPM), Working pressure (PSI), and Hose length (ft).
  2. Set Line type (1=suction, 2=return, 3=pressure), Fluid specific gravity, and Fluid viscosity (cSt).
  3. Adjust Number of fittings as needed.
  4. Review the Recommended SAE dash size result.
  5. Use Hose ID (inches) and Minimum required ID (in) to inform your decision.

What each input means

Flow rate (GPM)
Hydraulic flow rate in gallons per minute.
Working pressure (PSI)
Maximum system working pressure.
Hose length (ft)
Total hose run length in feet.
Line type (1=suction, 2=return, 3=pressure)
Suction lines need larger ID (low velocity); pressure lines allow higher velocity.
Fluid specific gravity
Hydraulic fluid specific gravity (0.87 typical for petroleum oil).
Fluid viscosity (cSt)
Kinematic viscosity at operating temperature (32 cSt typical for ISO VG 32).
Number of fittings
Number of hose end fittings and adapters in the run.

What each result means

Recommended SAE dash size
SAE dash size (-4, -6, -8, etc.) for the hose assembly.
Hose ID (inches)
Inner diameter of the selected hose.
Minimum required ID (in)
Calculated minimum ID to stay within velocity limits.
Actual velocity (ft/s)
Fluid velocity with the selected hose size.
Total pressure drop (PSI)
Pressure loss through hose and fittings.
Reynolds number
Flow regime indicator (<2300 = laminar, >4000 = turbulent).
Pressure rating usage (%)
Working pressure as percentage of SAE 100R2AT hose rating.
Power loss (HP)
Hydraulic power lost to friction in the hose run.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Flow rate (GPM) = 10, Working pressure (PSI) = 3000, Hose length (ft) = 10, Line type (1=suction, 2=return, 3=pressure) = 3 = 7 input(s) provided
  2. Calculate Recommended SAE dash size
    Recommended SAE dash size
    8 = 8
  3. Calculate Hose ID
    Hose ID
    0.5 = 0.5
  4. Calculate Minimum required ID
    Minimum required ID = sqrt(0.3208 * flowGpm / maxVelocity)
    0.4 = 0.4

Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.

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