Math & Numbers

Reynolds Number Calculator (Re=ρvD/μ, Laminar/Transitional/Turbulent)

Compute the Reynolds number Re = ρ·v·D/μ (dynamic viscosity) or Re = v·D/ν (kinematic viscosity, ν = μ/ρ) and classify the flow regime: Re < 2300 laminar, 2300 ≤ Re < 4000 transitional, Re ≥ 4000 turbulent. Diameter accepted in m/cm/mm. In dynamic mode the kinematic viscosity ν = μ/ρ is also returned. For internal pipe flow and general fluid-mechanics regime analysis.

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/reynolds-number-calculator' \
  -H 'Content-Type: application/json' \
  -d '{"solveFor":"dynamic","density":1000,"velocity":2,"diameter":0.05,"diameterUnit":"m","dynamicViscosity":0.001,"kinematicViscosity":0,"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/reynolds-number-calculator

Parameters

Name	Type	Required	Description
solveFor	select	No	Dynamic mode takes ρ, v, D, μ and also computes ν = μ/ρ. Kinematic mode takes v, D, ν directly.
density	number	No	Fluid density ρ (kg/m³). Required when Solve For = Dynamic.
velocity	number	Yes	Mean flow velocity v (m/s).
diameter	number	Yes	Characteristic length / hydraulic 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-reynolds-number-calculator": {
      "name": "reynolds-number-calculator",
      "description": "Compute the Reynolds number Re = ρ·v·D/μ (dynamic viscosity) or Re = v·D/ν (kinematic viscosity, ν = μ/ρ) and classify the flow regime: Re < 2300 laminar, 2300 ≤ Re < 4000 transitional, Re ≥ 4000 turbulent. Diameter accepted in m/cm/mm. In dynamic mode the kinematic viscosity ν = μ/ρ is also returned. For internal pipe flow and general fluid-mechanics regime analysis.",
      "baseUrl": "https://api.elysiatools.com/mcp/sse?toolId=reynolds-number-calculator",
      "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": "reynolds-number-calculator",
    "arguments": {
  "solveFor": "dynamic",
  "density": 1000,
  "velocity": 2,
  "diameter": 0.05,
  "diameterUnit": "m",
  "dynamicViscosity": 0.001,
  "kinematicViscosity": 0,
  "decimalPlaces": 4
}
  }
}

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