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Water Head Calculator

Gross and net head for a hydro scheme after pipe friction losses.

Enter values

Results update as you type.

Result

Net head

18.199 m

Friction is eating more than 15% of your head — use a larger penstock.

Gross head
25 m
Friction loss
6.801 m
Loss as a share of gross head
27.2%
Pressure at the turbine
1.7847 bar
Velocity in the penstock
2.829 m/s
Power at 70% efficiency
6,246.6 W

About the Water Head Calculator

Gross and net head for a hydro scheme after pipe friction losses.

Also known as: gross head calculator, net head hydro, head loss hydro, pressure head calculator.

How to use this calculator

  1. Enter gross head (vertical drop), penstock length, pipe diameter, flow rate and the other fields.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

net head = gross head − friction loss

Worked example

Using the values pre-filled in the calculator above:

  • Gross head (vertical drop) = 25 m
  • Penstock length = 150 m
  • Pipe diameter = 150 mm
  • Flow rate = 50 L/s
  • Hazen-Williams C = 140

the calculator returns:

  • Net head: 18.199 m
  • Gross head: 25 m
  • Friction loss: 6.801 m
  • Loss as a share of gross head: 27.2%