Velocity Pressure Calculator
Convert between air velocity and velocity pressure for pitot traverses.
US techs use V(fpm) = 4005×√VP(in wg) — that 4005 is this same equation in disguise at standard density.
Formula
Velocity Pressure Calculator is a free velocity pressure for HVAC designers, technicians and energy auditors — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Velocity Pressure Calculator
Convert between air velocity and velocity pressure for pitot traverses. The calculation implements VP = ½·ρ·V²; V = √(2·VP/ρ) ≈ 1.29·√VP (std air) (ASHRAE Fundamentals, ch. 37 — measurement). US techs use V(fpm) = 4005×√VP(in wg) — that 4005 is this same equation in disguise at standard density.
How to use Velocity Pressure Calculator
- 1Enter Air velocity in m/s.
- 2Enter Air density in kg/m³.
- 3Read Velocity pressure instantly — no submit button needed.
- 4Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Velocity Pressure Calculator?
- ✓Implements the standard formula — VP = ½·ρ·V²; V = √(2·VP/ρ) ≈ 1.29·√VP (std air)
- ✓Reference cited on-page: ASHRAE Fundamentals, ch. 37 — measurement
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Live worked example: the substitution recomputes from your numbers
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Velocity Pressure Calculator use?+
It computes VP = ½·ρ·V²; V = √(2·VP/ρ) ≈ 1.29·√VP (std air), per ASHRAE Fundamentals, ch. 37 — measurement. The formula is displayed under the result along with a worked example substituted with your own inputs.
What should I keep in mind when using this calculator?+
US techs use V(fpm) = 4005×√VP(in wg) — that 4005 is this same equation in disguise at standard density.
Is this based on ASHRAE methods?+
The calculations follow the standard ASHRAE/ISHRAE formulations cited under the result, simplified where industry practice does the same. For permit-grade design, confirm with the full code procedure.
Is the Velocity Pressure Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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