Turn velocity into equivalent pressure head instantly here today. Switch units and check gravity assumptions. Use clean exports to share calculations with teams fast.
Velocity head is the kinetic-energy head in fluid flow:
hᵥ = v² / (2g)
| Velocity, v (m/s) | Gravity, g (m/s²) | Velocity head, hᵥ (m) | Notes |
|---|---|---|---|
| 2.0 | 9.80665 | 0.204 | Low-speed flow in small pipes |
| 5.0 | 9.80665 | 1.275 | Typical distribution velocity |
| 10.0 | 9.80665 | 5.099 | Higher kinetic head, check losses |
Velocity head converts flow speed into an equivalent elevation head. It represents kinetic energy per unit weight in the Bernoulli equation. In SI terms, a speed of 5 m/s gives hᵥ ≈ 1.275 m when g = 9.80665 m/s², matching the example table.
Engineers use velocity head to compare energy terms consistently. In piping, velocity head helps interpret how speed changes influence total head, pump sizing, and downstream equipment. Higher velocity generally increases noise, vibration risk, and erosion in fittings.
For water distribution, common velocities are roughly 1–3 m/s, depending on noise and headloss limits. Around 2 m/s, hᵥ is about 0.204 m. At 10 m/s, hᵥ rises to about 5.099 m, which can be significant in energy budgets.
Head can be converted to pressure using p = ρgh. For water near 20°C (ρ ≈ 1000 kg/m³), 1 m of head corresponds to about 9.81 kPa. This makes velocity head useful for estimating the pressure change associated with sudden velocity variations.
This calculator supports m/s and ft/s for velocity, and meters or feet for head. Gravity must match the chosen unit system. Standard Earth gravity is 9.80665 m/s² (or 32.174 ft/s²). Small g changes slightly shift results at high speeds.
Velocity head scales with v², so doubling velocity increases hᵥ by a factor of four. This is why modest speed increases can strongly affect energy terms and allowable headloss. It also explains why high-velocity systems demand careful material and support selection.
Use “Find Velocity Head” when you know velocity and gravity. Use “Find Velocity” when you know the available head term and gravity. Use “Find Gravity” mainly for verification or educational checks where measured head and velocity are available.
Velocity head is not the same as friction loss, but it often appears alongside loss terms (major and minor losses). When comparing two pipe sections, changes in velocity head indicate energy redistribution, while losses represent energy dissipation.
It expresses kinetic energy as an equivalent head term in Bernoulli calculations. It helps compare velocity effects against elevation head, pressure head, and loss terms in a consistent unit of length.
Because hᵥ depends on v². If velocity doubles, velocity head becomes four times larger. This square relationship makes high-speed flows much more energy-intensive and more sensitive to measurement errors.
No. Velocity head is an energy term related to speed. Head loss is energy dissipated due to friction and fittings. Velocity head can change without losses, but losses always reduce total head.
Use standard Earth gravity for most engineering work: 9.80665 m/s² or 32.174 ft/s². If you must match a local standard or textbook value, choose the approximation option or enter g manually.
Yes. Select “Find Velocity” and enter hᵥ and g. The calculator uses v = √(2ghᵥ). This is useful when velocity head is known from energy-grade-line calculations or test data.
A zero velocity head indicates zero velocity. In “Find Velocity” mode, entering hᵥ = 0 returns v = 0. For “Find Gravity,” hᵥ must be positive to avoid division by zero.
They are computed using standard gravity and the exact formula hᵥ = v²/(2g). Your results may differ slightly if you use a different g value or switch to feet-based units.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.