Transparent continuity calculation

Pipe Flow Rate & Velocity Calculator

Convert between water flow and velocity using actual internal pipe diameter, then estimate fill time for a target volume.

Enter your values

Example values demonstrate the method; they are not product recommendations.

Your result

Enter measured or nameplate values to calculate.

Method

Flow = cross-sectional area × average velocity. The calculation uses circular area from entered internal diameter; fill time uses constant calculated flow.

Important limits

A diameter and velocity alone do not predict available flow. Actual flow depends on pressure, pump curve, elevation, losses, valves and pipe condition.

Technical reference

Calculate water flow rate or pipe velocity from internal diameter using the continuity equation.

What to enter

Use current, project-specific values for pipe internal diameter and known flow-rate or velocity value. Check every unit before calculating and compare like-for-like inputs. The template controls the actual fields and calculations; this supporting copy does not replace its labels, formulas or result logic.

How to use the result

The result is a continuity-equation conversion. It does not by itself confirm pressure loss, pipe rating, pump duty or acceptable design velocity.

Before making a decision

Verify source measurements, equipment specifications and operating conditions. Have a qualified professional review the final selection, safety and installation requirements before purchase, connection or construction.