What this calculator does
Bernoulli's equation works out pressure at one point in a steady, frictionless flow from conditions at another point. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
Formulap₁ + ½ρv₁² + ρgh₁ = p₂ + ½ρv₂² + ρgh₂ (steady, incompressible, inviscid flow)
The inputs explained
| Field | What to enter |
|---|---|
| Pressure at point 1 (Pa) | A number, measured in Pa. Starts at 200000. |
| Fluid density (water = 1000) (kg/m³) | A number, measured in kg/m³. Starts at 1000. |
| Speed at point 1 (m/s) | A number, measured in m/s. Starts at 2. |
| Elevation at point 1 (m) | A number, measured in m. Starts at 0. |
| Speed at point 2 (m/s) | A number, measured in m/s. Starts at 5. |
| Elevation at point 2 (m) | A number, measured in m. Starts at 2. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with pressure at point 1
Every other input is held at the calculator’s starting values while pressure at point 1 varies. Select any row to load that scenario into the calculator.
How the answer changes with pressure at point 1
| Pressure at point 1 (Pa) | Pressure at point 2 | Pressure at point 2 | Change from the dynamic-pressure term |
|---|---|---|---|
| 100,000 | 69,887 Pa | 69.887 kPa | -10,500 Pa |
| 150,000 | 119,887 Pa | 119.887 kPa | -10,500 Pa |
| 200,000 | 169,887 Pa | 169.887 kPa | -10,500 Pa |
| 300,000 | 269,887 Pa | 269.887 kPa | -10,500 Pa |
| 400,000 | 369,887 Pa | 369.887 kPa | -10,500 Pa |
| 600,000 | 569,887 Pa | 569.887 kPa | -10,500 Pa |