When to use this calculator
Estimate static-pressure change due to a speed change in ideal horizontal flow. Horizontal, steady, incompressible, inviscid streamline model; no pumps or friction losses.
Explore the fluids & flow calculators for other questions in this topic. For a related calculation, use the Buoyant Force Calculator: Find buoyancy from displaced fluid volume and density.
PUTTING IT INTO PRACTICE
Bernoulli Pressure Difference: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Density (kg/m³) | 1,000 |
| Initial speed (m/s) | 1 |
| Final speed (m/s) | 3 |
| Result | -4,000 Pa |
- Check the input labels and enter the example values above.
- Apply the relationship: P₂−P₁ = density × (speed₁²−speed₂²)/2.
- The result is -4,000 Pa, rounded for display.
How to interpret your result
Horizontal, steady, incompressible, inviscid streamline model; no pumps or friction losses.
Use the fluid properties at the relevant conditions. Gauge pressure is measured relative to a reference and differs from absolute pressure. Average flow velocity and characteristic length must match the geometry being modelled.
Frequently asked questions
Should hydrostatic pressure be added to atmospheric pressure?
Add the surface absolute pressure when an absolute result is needed. The basic liquid-column calculation alone gives the pressure increase with depth.
When is the bernoulli pressure difference calculator useful?
Estimate static-pressure change due to a speed change in ideal horizontal flow. Horizontal, steady, incompressible, inviscid streamline model; no pumps or friction losses.
How do I use the bernoulli pressure difference calculator?
Enter density (kg/m³), initial speed (m/s), final speed (m/s). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
P₂−P₁ = density × (speed₁²−speed₂²)/2.
What should I check before using the result?
Horizontal, steady, incompressible, inviscid streamline model; no pumps or friction losses.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
Further reading
For background on this topic, see OpenStax: fluids, density and pressure ↗. This is a topic reference, not an external review or endorsement of this tool.
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