Orifice Flow Calculator
Calculate liquid flow rate through a sharp-edged orifice plate from orifice diameter, pressure drop, discharge coefficient and fluid density — results in L/s, L/min, m³/h and US gpm.
Input
Differential pressure across the orifice.
About 0.60–0.62 for a sharp-edged orifice with a turbulent jet.
Water at 20 °C is about 998 kg/m³.
When given, applies the velocity-of-approach correction 1/√(1−β⁴). Must be larger than the orifice.
Output
| Metric | Value |
|---|---|
| No data yet | |
More ways to use this tool
REST API
curl -X POST https://api.iotools.cloud/v1/tool/orifice-flow-calculator \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"orificeDiameter": "50",
"pressureDrop": "100",
"dischargeCoefficient": "0.61",
"density": "1000"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `orifice-flow-calculator` tool (Orifice Flow Calculator) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.
Embed widget
<iframe
src="https://iotools.cloud/embed/orifice-flow-calculator/"
width="100%" height="520" frameborder="0" scrolling="no" loading="lazy"
title="Orifice Flow Calculator — iotools.cloud"
sandbox="allow-scripts allow-forms allow-same-origin allow-downloads allow-popups allow-popups-to-escape-sandbox"
allow="clipboard-write"
style="width:100%;border:1px solid #e5e7eb;border-radius:12px;overflow:hidden"></iframe>
<script src="https://iotools.cloud/embed.js" async></script>Drop this into your own page — free, no key required, just a link back.
| Cost per API/MCP call | From 5 credits |
|---|---|
| Need more credits? | View pricing |
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Guides
Estimate how much liquid passes through a sharp-edged orifice from its diameter and the pressure drop across it. Enter the orifice diameter and ΔP, adjust the discharge coefficient and fluid density if needed, and get the flow in m³/s, L/s, L/min, m³/h and US gallons per minute, plus mass flow and jet velocity.
The formula
For an incompressible fluid: Q = Cd · A · √(2·ΔP / ρ), where A is the orifice area, ΔP the pressure drop and ρ the fluid density. If you also enter the pipe diameter, the calculator applies the velocity-of-approach correction 1 / √(1 − β⁴) with β = orifice diameter ÷ pipe diameter.
How to use it
- Enter the orifice diameter (mm) and the pressure drop (kPa).
- Keep Cd at 0.61 for a sharp-edged orifice, or enter your own value.
- Change the density for anything other than water (about 1000 kg/m³).
- Optionally enter the pipe diameter to include the approach-velocity effect.
All calculations run in your browser — nothing is uploaded.
What discharge coefficient should I use?
0.60–0.62 is typical for a thin, sharp-edged orifice with a fully turbulent jet. Rounded or short-tube entrances raise it toward 0.8–0.98; check your orifice's datasheet when you have one.
Does this work for gases?
No. The formula assumes an incompressible liquid. Gases need an expansion factor once the pressure drop is more than a few percent of the upstream pressure.