Pressure drop calculator helps you to calculate fluid flow rate through closed pipe. The calculation includes pipe friction factor f and local losses with resistance coefficient K calculation. It can be used for non-compressible flow like liquids as well as for low velocity, short distance gas stream.

- pressure drop
- flow rate
- friction coefficient
- flow velocity

In Selection section you can select values to input. Not selected values will be calculated. You select between:

- calculation type - pressure drop or flow rate
- pipe shape - circular or rectangle
- volume and mass flow rate
- pressure on pipe start or pipe end
- kinematic or dynamic viscosity

In Report section you have instant calculation report for input values. From there you can copy/paste report to your text editor.

- Darcy-Weisbach equation based
- Laminar and turbulent flow regime
- Round and rectangle pipe
- Incompressible flow only

- q - volumetric flow rate
- Fluid flow rate in terms of units of volume per unit of time
- ṁ - mass flow rate
- Fluid flow rate in terms of units of mass per unit of time
- L - pipe length
- Length of a pipe in which pressure drop is calculated
- D - pipe diameter
- Internal circular pipe diameter
- H - channel height
- The height of channel for rectangle shaped pipe
- W - channel width
- The width of channel for rectangle shape pipe
- kr - pipe roughness
- Pipe internal surface roughness
- V - velocity
- Flow velocity in terms of units of distance per unit of time
- A - area
- Internal pipe cross section area
- f - friction coefficient
- Coefficient of friction for pressure drop due to friction calculation
- Re - Reynolds number
- Dimensionless number representing viscous versus inertial forces ratio
- δ - boundary layer thickness
- Thickness of laminar layer formed in turbulent flow connected to pipe wall surface
- ρ - fluid density
- Mass per unit of volume
- ν - kinematic viscosity
- Result of fluid particles colliding to each other and moving at different velocities in terms of area per square unit of time
- μ - dynamic viscosity
- Result of fluid particles colliding to each other and moving at different velocities in terms of mass per square unit of distance and time
- K - resistance coefficient
- Coefficient used for calculation of minor losses due to local resistances in pipe line like bends, tees, reducers, valves, etc.
- p
_{1}- pressure on the inlet - Absolute pressure at the pipe start
- p
_{2}- pressure on the outlet - Absolute pressure at the pipe end
- p
_{1}- p_{2}- pressure drop - Pressure difference between pipe start and pipe end

- Related links:
- Read more on Darcy-Weisbach equation
- Relation between Reynolds number, relative roughness and friction coefficient - Moody chart
- Find more about Osborne Reynolds, prominent innovator on Wikipedia.