Professional Plumbing Calculators
Free, code-compliant tools for plumbers, engineers, and contractors. IPC/UPC standard references included.
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Pipe Sizing Calculator
Determine optimal pipe diameter based on flow rate, velocity, and material. Includes friction loss estimates.
IPC Table 604.3Fixture Units Calculator
Calculate total fixture units (WSFU/DFU) for residential and commercial buildings per code requirements.
IPC Table 604.4Pressure Drop Calculator
Calculate pressure loss through pipes using Hazen-Williams equation. Account for fittings and elevation.
Hazen-WilliamsWater Heater Sizing
Size tank and tankless water heaters based on peak demand, fixture count, and household size.
First Hour RatingFlow Rate Calculator
Calculate flow rate from pressure, pipe size, and length. Convert between GPM, LPM, and CFM.
Unit ConverterWhy Use FreePlumbing.tools?
Mobile-First Design
Works great on job sites with spotty cell service. Fast loading, no bloat.
Code Compliant
References IPC and UPC standards. Professional credibility for inspectors and clients.
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Your inputs are automatically saved locally. Come back anytime without re-entering data.
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Code Standards Reference
IPC - International Plumbing Code
Used in most US states. Our calculators reference IPC 2021 tables for pipe sizing, fixture units, and water distribution.
UPC - Uniform Plumbing Code
Primary code in California, Washington, and other western states. Calculators include UPC-specific values where applicable.