CALCULATORS / PUMPS, FANS AND VENTILATION

Pump hydraulic and input power calculator

Idealized steady hydraulic lift, efficiency is assumed

pumps-pump-power.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	hydraulicPowerW	inputPowerW
	98.1	163.5
	196.2	327

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

power budget163.50 W✓ passes

BASELINE INPUTS

density1000 kg/m^3gravity9.81 m/s^2flow0.002 m^3/s0.0010.005head5 m215efficiency0.6

CALCULATED

hydraulicPower98.1 W

inputPower163.5 W

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Idealized steady hydraulic lift, efficiency is assumed
density = 1000 kg/m^3
gravity = 9.81 m/s^2
flow = 0.002 m^3/s in 0.001..0.005
head = 5 m in 2..15
efficiency = 0.6 "Assumed overall pump efficiency"
hydraulicPower := density * gravity * flow * head [W]
inputPower := hydraulicPower / efficiency [W]
check power budget: inputPower <= 250 W
scenario high head: head = 10 m

Calculated from your source · not saved

Baseline · Baseline

power budget163.50 W ✓ passes

high head · high head

power budget327.00 W × fails

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

hydraulic power: hydraulicPower = density * gravity * flow * head [W]
input power: inputPower = hydraulicPower / efficiency [W]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

density: 1000 kg/m^3
gravity: 9.81 m/s^2
flow: 0.002 m^3/s
head: 5 m
efficiency: 0.6

Calculated

hydraulic power: 98.1 W
input power: 163.5 W

Assumptions and limits

Idealized steady hydraulic lift, efficiency is assumed

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Pump hydraulic and input power. Inputs: flow; head or pressure rise; efficiency. Outputs: hydraulic, shaft and electrical power. Model scope: Measured or manufacturer curves and declared fluid conditions. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: flow, head or pressure rise, efficiency
Outputs: hydraulic, shaft and electrical power
Modes: calculate, compare, sweep
Drawing: System and equipment curves

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS