How to Calculate CV for Globe, Gate, and Check Valves (with Tables)
Understand valve CV calculation, key equations, and real-world examples
Overview
The CV (flow coefficient) measures how much flow a valve allows at a given pressure drop. It's essential for proper valve sizing and system design—especially for globe valves, gate valves, and check valves.
In this guide, you'll learn:
- What Is Valve CV?
- CV Formula and Units
- CV Calculation by Valve Type
- CV Tables: Globe, Gate, and Check Valves
- Factors That Affect Valve CV
- Related Resources
- Conclusion: Selecting the Right CV
What Is Valve CV?
CV (flow coefficient) is the number of gallons of water per minute (GPM) at 60°F that will flow through a valve with a 1 psi pressure drop.
It’s a performance rating used to compare valve flow capacity across different designs and sizes.
CV Formula and Units
For liquids:
CV = Q × √(SG / ΔP)
- Q = Flow rate (GPM)
- SG = Specific gravity of fluid
- ΔP = Pressure drop (psi)
For gases: Use compressible flow formulas or manufacturer sizing software.
CV Calculation by Valve Type
Different valve types have different internal geometries, which impact flow and CV:
- Globe valves have high control precision and medium CV
- Gate valves are full-port and typically have high CV
- Check valves vary widely; swing and lift types differ
CV Tables: Globe, Gate, and Check Valves
CV Table: Globe Valves
| Size (inches) | CV |
|---|---|
| 1" | 7.5 – 12 |
| 2" | 25 – 45 |
| 4" | 90 – 160 |
| 6" | 220 – 360 |
CV Table: Gate Valves
| Size (inches) | CV |
|---|---|
| 1" | 40 – 45 |
| 2" | 120 – 130 |
| 4" | 400 – 500 |
| 6" | 800 – 1100 |
CV Table: Swing Check Valves
| Size (inches) | CV |
|---|---|
| 1" | 20 – 28 |
| 2" | 75 – 95 |
| 4" | 270 – 380 |
| 6" | 640 – 880 |
Download Full CV Table (PDF) →
Common Factors Affecting CV
- Valve design and flow path geometry
- Trim and seat material
- Port size and end connections
- Open/close position (especially in globe valves)
Related Resources
Conclusion: Selecting the Right CV
The correct valve CV ensures system efficiency and safe flow control. For manual or control applications, globe valves offer reliable CV predictability. For isolation, gate valves offer high CV with low pressure drop.
Need help selecting or sizing a valve?
đź“ž Contact SVF’s application engineers or try our interactive CV calculator →