Head Loss Calculator

Head Loss Calculator helps you calculate friction and pressure loss in water piping systems using the Hazen-Williams equation, Darcy-Weisbach formula, and Swamee-Jain friction factor method. Instantly determine pressure drop in any pipe material over any distance. Support 11 pipe materials from copper to galvanized steel with accurate C-coefficients. Works 100% offline on the job site. Useful for sizing booster pumps, pressure reducing valves, and water supply systems.

FEATURES
• 2 Calculation Methods: Hazen-Williams equation (traditional plumbing) and Darcy-Weisbach formula with Swamee-Jain friction factor (engineering method)
• 11 Pipe Materials: copper, PVC, CPVC, PEX, HDPE, stainless steel, galvanized steel, black iron, cast iron (new and old/corroded), and concrete — with published C-coefficients and roughness factors
• Flow Rate Units: GPM (US gallons per minute), L/s (liters per second), and CFM (cubic feet per minute)
• Pipe Diameter Range: Calculate loss for 1/2-inch through 4-inch and larger pipes
• Flow Velocity Calculation: Automatic velocity calculation with high-velocity warning (>8 ft/s indicates sizing issue)
• Results in Multiple Units: Pressure loss displayed in PSI and feet of head for system analysis
• Pipe Length Support: Calculate loss for pipe runs from 10 feet to 500+ feet

HOW IT WORKS
1. Enter water flow rate (GPM) from fixture unit calculations
2. Select pipe material (copper, PVC, galvanized steel, etc.)
3. Enter pipe diameter and total run length
4. Choose calculation method (Hazen-Williams or Darcy-Weisbach)
5. See pressure loss in PSI and feet of head
6. Check velocity warning - velocities >8 ft/s indicate undersized pipe

PERFECT FOR
• Plumbers designing water supply systems with booster pumps
• Engineers calculating pressure loss for system analysis
• Contractors estimating pump requirements
• Mechanical estimators sizing pressure tanks and regulators
• Plumbing inspectors verifying system design
• Facilities managers troubleshooting low pressure issues

OPTIONAL PRO UPGRADE — $2.99 ONE-TIME IN-APP PURCHASE
The following features require a separate one-time in-app purchase. They are not required to use the calculator:
• Unlimited saved calculation history
• PDF export of results
• Dark theme
• Ad-free experience

STANDARDS & COMPLIANCE
Hazen-Williams Equation - traditional plumbing industry standard, Darcy-Weisbach Formula with Swamee-Jain Friction Factor - engineering standards for pipe friction calculation, Material-specific C-coefficients and roughness factors per engineering references, IPC water supply system design guidance.

PERFECT FOR
• Plumbing engineers and designers
• Plumbing contractors and estimators
• Mechanical engineers
• Facilities and building managers
• Plumbing inspectors
• Pump and equipment specialists

OFFLINE & PRIVACY
• Works 100% offline - calculate pressure loss anywhere
• No account required - instant calculations
• No data collection - all results stored locally
• No internet dependency

Part of PlumbTools Suite - professional plumbing and engineering calculator tools. Calculate pressure loss accurately, size pumps correctly, and optimize water system design with precise head loss calculations.

Recent changes:
Added a link to TradeTools — the one-app version of this calculator and 61 more, for HVAC, electrical, plumbing, fire protection, solar and carpentry. Nothing else changed.