When to use this calculator
Pressure drop across a pipe run determines pump sizing, whether a gravity-fed system will deliver adequate flow, and whether a pipe diameter is adequate for a given flow rate. This tool solves the Darcy-Weisbach equation directly rather than the older, less accurate Hazen-Williams approximation, and uses the Swamee-Jain formula to solve for the Darcy friction factor without iteration.
Typical uses: sizing pump head for HVAC and plumbing systems, checking whether an existing pipe run can support a higher flow rate, comparing pipe materials or diameters before installation, and coursework in fluid mechanics.