Math & Numbers

Pipe Pressure Drop Calculator (Darcy-Weisbach)

Compute the Darcy-Weisbach major (friction) pressure drop in a straight pipe: ΔP = f·(L/D)·(ρ·v²/2) Pa and head loss h_f = f·(L/D)·v²/(2g) m. The user supplies the Darcy friction factor f (not the Fanning factor). Length in m/km/ft, diameter in m/cm/mm/inch, density in kg/m³/g/cm³/lb/ft³ — all normalised to SI internally. Returns ΔP in Pa, kPa and bar, and head loss in m and ft. Gravity defaults to 9.81 m/s² and may be overridden.

json· JSON resultOpen tool

Quick start

Call this tool from your code in three languages.

cURL

curl -X POST 'https://api.elysiatools.com/en/api/tools/pipe-pressure-drop-darcy' \
  -H 'Content-Type: application/json' \
  -d '{"frictionFactor":0.02,"pipeLength":100,"pipeLengthUnit":"m","diameter":0.05,"diameterUnit":"m","density":1000,"densityUnit":"kg/m³","velocity":2,"gravity":9.81,"decimalPlaces":4}'

API reference

Send a POST request with your inputs as JSON. File parameters require a separate upload first.

Endpoint

HTTP

POST https://api.elysiatools.com/en/api/tools/pipe-pressure-drop-darcy

Parameters

Name	Type	Required	Description
frictionFactor	number	Yes	Darcy friction factor f (also called Moody / Darcy-Weisbach factor). NOTE: this is NOT the Fanning friction factor (f_Darcy = 4·f_Fanning). Obtain f from a Moody chart or the Colebrook-White correlation.
pipeLength	number	Yes	Pipe length L in the selected Length Unit.
pipeLengthUnit	select	No	—
diameter	number	Yes	Internal pipe diameter D in the selected Diameter Unit.
diameterUnit	select

MCP integration

Add this tool to your Model Context Protocol server so AI agents can list and call it.

Server configuration

Add this block to your MCP client configuration:

mcp.json

{
  "mcpServers": {
    "elysiatools-pipe-pressure-drop-darcy": {
      "name": "pipe-pressure-drop-darcy",
      "description": "Compute the Darcy-Weisbach major (friction) pressure drop in a straight pipe: ΔP = f·(L/D)·(ρ·v²/2) Pa and head loss h_f = f·(L/D)·v²/(2g) m. The user supplies the Darcy friction factor f (not the Fanning factor). Length in m/km/ft, diameter in m/cm/mm/inch, density in kg/m³/g/cm³/lb/ft³ — all normalised to SI internally. Returns ΔP in Pa, kPa and bar, and head loss in m and ft. Gravity defaults to 9.81 m/s² and may be overridden.",
      "baseUrl": "https://api.elysiatools.com/mcp/sse?toolId=pipe-pressure-drop-darcy",
      "command": "",
      "args": [],
      "env": {},
      "isActive": true,
      "type": "sse"
    }
  }
}

List available tools

After connecting to the SSE endpoint, list the exposed tools:

tools/list

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/list"
}

Call this tool

Invoke the tool by its id, passing arguments built from its parameters:

tools/call

{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "tools/call",
  "params": {
    "name": "pipe-pressure-drop-darcy",
    "arguments": {
  "frictionFactor": 0.02,
  "pipeLength": 100,
  "pipeLengthUnit": "m",
  "diameter": 0.05,
  "diameterUnit": "m",
  "density": 1000,
  "densityUnit": "kg/m³",
  "velocity": 2,
  "gravity": 9.81,
  "decimalPlaces": 4
}
  }
}

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