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Valve Kv Sizing Calculator
Enter duty flow and allowed pressure drop — required Kv updates instantly.
Formula
Kv = Q · √(SG / Δp)
Typical Full-Open Kv by Valve Size (globe)
| DN | Kv (m³/h) |
|---|---|
| 15 | 2.5 |
| 20 | 4.0 |
| 25 | 6.3 |
| 32 | 10 |
| 40 | 16 |
| 50 | 25 |
| 65 | 40 |
| 80 | 63 |
| 100 | 100 |
Good practice: size the valve so it operates 20–80% open at normal duty — pick a Kv roughly 1.5–2× the required value.
FAQ
Why not pick the exact required Kv?
A valve at 100% open has no control authority. Oversizing ~1.5× keeps the plug in its working range.
Does viscosity change Kv?
Yes — viscous liquids need correction factors above a Reynolds threshold. This calculator assumes water-like fluids.