Calculate fluid velocity from pressure and density with flexible units. See results above the form. Export tables, compare cases, and verify engineering assumptions easily.
| Pressure | Density Input | Diameter | Cd | Velocity | Flow |
|---|---|---|---|---|---|
| 30 PSI | SG 1.00 | 2 in | 0.98 | 65.40 ft/s | 640.35 gpm |
| 18 PSI | SG 0.85 | 1.5 in | 0.95 | 49.91 ft/s | 274.90 gpm |
| 75 PSI | 1,260 kg/m³ | 50 mm | 0.92 | 81.86 ft/s | 776.52 gpm |
1. Pressure conversion: Convert the entered pressure differential into pascals.
2. Density selection: Use either specific gravity × 1000, or convert custom density into kg/m³.
3. Efficiency adjustment: Effective pressure = Pressure × Efficiency.
4. Elevation correction: Hydrostatic penalty = ρ × g × elevation gain.
5. Net pressure: Net pressure = Effective pressure − Hydrostatic penalty.
6. Ideal velocity: v = √(2ΔP / ρ).
7. Adjusted velocity: Actual velocity = Ideal velocity × discharge coefficient.
8. Flow rate: Q = A × v, where A = πd²/4.
9. Reynolds number: Re = ρvd / μ.
10. Velocity head: hv = v² / 2g.
Enter the pressure differential first. Select the unit that matches your instrument reading.
Choose specific gravity for common liquids. Choose custom density for fluids with known density values.
Enter discharge coefficient to model nozzle, outlet, or system losses. Use efficiency to include overall usable pressure.
Enter elevation gain when the fluid must rise. This reduces the net pressure available for velocity.
Add pipe inside diameter to estimate flow rate. Add viscosity when you want Reynolds number and flow regime output.
Press the calculate button. The result will appear above the form. Use the export buttons to save CSV or PDF copies.
A PSI velocity calculator converts pressure energy into flow velocity. Engineers use it for nozzles, pipelines, test rigs, water systems, and process equipment. The method is based on Bernoulli flow logic. Pressure difference drives motion. Fluid density resists acceleration. The balance between both values sets theoretical velocity.
Density is critical in every pressure-to-velocity calculation. A dense liquid reaches a lower speed than a light liquid under the same pressure differential. Specific gravity is often enough for water-based work. Custom density is better for oils, chemicals, slurries, and specialty fluids. This calculator supports both approaches.
Real systems are not ideal. Fittings, valves, outlet shapes, rough surfaces, and internal restrictions reduce usable energy. That is why this calculator includes discharge coefficient and efficiency. These inputs make the result more practical. Elevation gain is also included. Vertical rise consumes pressure and lowers final velocity.
Velocity alone is not always enough. Engineers also need discharge volume. Once pipe diameter is known, the calculator converts speed into area-based flow rate. The page shows m³/s, L/s, m³/h, and gpm. This helps with pump checks, line sizing, outlet comparison, and equipment selection.
Dynamic viscosity lets the calculator estimate Reynolds number. That extra output helps identify laminar, transitional, or turbulent flow. Flow regime affects friction, mixing, heat transfer, and measurement stability. When viscosity is known, the result becomes more valuable for design review and troubleshooting.
This tool works best for incompressible or near-incompressible conditions. Very high gas speeds may require compressible flow methods. Use the result as a strong engineering estimate, then confirm with detailed hydraulic, piping, or CFD analysis when risk is high. For early design, audits, and quick checks, this calculator is efficient and reliable.
It estimates fluid velocity from a pressure differential. It also estimates flow rate, velocity head, dynamic pressure, and Reynolds number when viscosity is provided.
No. You can enter psi, kPa, bar, or Pa. The tool converts everything internally, then returns consistent engineering outputs.
Specific gravity is a fast way to estimate density. It is especially helpful for water-like liquids when full density data is not immediately available.
It reduces ideal velocity to a more realistic value. Use it when the outlet, nozzle, or geometry introduces non-ideal discharge behavior.
Raising fluid consumes pressure. The calculator subtracts hydrostatic pressure loss caused by vertical lift before estimating final velocity.
Diameter does not change theoretical outlet velocity from pressure alone. It changes flow area, which changes total volumetric flow rate.
It helps when you want flow regime insight. That matters for friction, mixing, pressure loss behavior, and general hydraulic interpretation.
It can provide a rough estimate at low gas velocities. For high-speed gas applications, use a compressible flow model for better accuracy.
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.