HYDRONIC ENGINEERING TOOL

Pipe Velocity / Flow Calculator

Solve circular-pipe volumetric flow, average velocity or internal diameter for quick hydronic checks.

Relate pipe flow, actual internal diameter and average velocity.

Explain this screen

Use this when: Checking a hydronic flow relationship with two known quantities.

This helps you: Solve the missing geometric quantity while keeping actual internal diameter explicit.

How to use it

Choose Solve velocity, Solve flow or Solve diameter.
Enter the other two quantities and their units.
Review the result before checking available pipe data and design criteria.

Before relying on it: Calculated internal diameter is not a nominal DN selection. Pipe schedule, friction, pump head and recommended velocity are not calculated here.

Show example inputs

Learning example only. These values are not measured data or recommended Project criteria.

Mode: Solve velocity
Flow: 10 L/s
Internal diameter: 100 mm

Starter inputs are for learning. Use your own values and explicitly sourced criteria for a job.

Volumetric flow

L/s

Fluid volume moving per unit time in the selected flow unit.

Help with volumetric flow

Where to find it: Use a measured or design flow for this pipe.

If you don’t know: If internal diameter and average velocity are known, choose Solve flow.

Flow unit

Internal pipe diameter

Actual inside diameter, not the nominal DN or outside diameter.

Help with internal pipe diameter

Where to find it: Use pipe/manufacturer data for the actual installed size and schedule.

If you don’t know: Find the actual inside diameter; a nominal DN value is not a substitute.

Diameter unit

RESULT1.2732 m/s

250.64 fpmInternal diameter: 100 mm

What this result means

The answer solves the circular internal-area flow relationship for the selected quantity.

Check: Calculated internal diameter is not a nominal DN selection. Pipe schedule, friction, pump head and recommended velocity are not calculated here.

Why this result?

The existing engine uses Q = A × V with A = πD²/4 for actual internal diameter.

Calculated from the current entered values; these values are not independently verified measurements.

Volumetric flow: 10 L/s
Internal pipe diameter: 100 mm

Related tools open separately. Enter the relevant values there; current inputs are not transferred or saved automatically.

Geometric flow check only. Diameter means actual internal diameter. This calculator does not determine pipe schedule, friction loss, pressure drop, pump head, fittings, Reynolds number, erosion/cavitation limits, or recommended design velocity.

Engineering Method & Assumptions

Uses Q = A × V with circular internal area A = πD²/4. It is suitable for quick hydronic flow/velocity checks when the actual internal diameter is known.

Scope

This tool uses actual internal diameter and the continuity relationship only. Pressure drop, friction, fittings, pipe schedule and pump selection remain outside this calculation.