Trap & Vent Calc Plumb

About this app

Trap & Vent Sizing Calculator helps you size trap arm distances and vent pipe diameters per the printed IPC: Table 909.1 (trap-to-vent distance), Section 906.2 (vent sizing rule) and Table 906.1 (stack vents). Instantly determine maximum allowable trap arm length and minimum vent pipe size for any DFU load and vent length. Useful for DWV system design, especially for island sinks and fixture groups requiring separate vent stacks. Works 100% offline on the job site. Eliminate trap and vent sizing errors, ensure full code compliance. FEATURES - Trap Arm Mode: Maximum trap-to-vent developed length per printed Table 909.1 (1-1/4" 5 ft through 4" 16 ft, with the required drain slope; water closets exempt per the 909.1 exception) - Vent Sizing Mode: Minimum vent diameter per the printed 906.2 rule — at least half the drain served, never below 1-1/4", one nominal size larger when the developed length exceeds 40 ft - Stack Vent Length Mode: Maximum developed length for stack vents and vent stacks per printed Table 906.1 (stack size + DFU; conservative next-higher DFU row) - Printed Table 906.1 data for stacks 1-1/4" through 8" stored exactly as published (app input covers 1-1/4"-4" stacks) - Printed Table 909.1 trap-arm distances with slopes (1/4" per ft through 2"; 1/8" per ft for 3" and 4") - 5 Trap/Drain Sizes: 1-1/4", 1-1/2", 2", 3", 4" - Code Notes: Every result cites the exact IPC table or section used HOW IT WORKS 1. Select calculation mode (trap arm length, vent size, or vent length) 2. Enter total DFU load on the vent 3. Enter trap size and vent pipe length 4. See IPC 2024 maximum distances and minimum vent sizes 5. Export chart to PDF for code inspection and permitting PERFECT FOR - Plumbers sizing trap arms for island sinks and fixture groups - Journeyman plumbers and apprentices learning vent sizing - Plumbing contractors designing complex vent systems - Mechanical estimators calculating material requirements - Plumbing inspectors verifying code compliance - Building code officials conducting plan reviews 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 IPC 2024 Table 906.1 - Vent Sizing for Continuous Vents and Vent Stacks, IPC 2024 Table 1002.1 - Trap Arm Distance Limitations, IPC Section 906 Vent Sizing, IPC Section 1002 Trap Arm Requirements, UPC (Uniform Plumbing Code) vent sizing requirements. PERFECT FOR - Professional plumbers and drainage contractors - Journeyman and apprentice plumbers - Mechanical engineers designing DWV systems - Plumbing inspectors and code officials - Building contractors and estimators - Plumbing educators and students OFFLINE & PRIVACY - Works 100% offline - design vent systems anywhere on site - No account required - instant calculations without signup - No data collection - all designs stored locally - No internet dependency Part of PlumbTools Suite - professional plumbing calculators for DWV system design. Size trap arms and vents accurately, ensure full IPC 2024 compliance, and speed up system design with accurate vent and trap sizing calculations.

What's new: - Trap-arm distances per the printed IPC Table 909.1 (5/6/8/12/16 ft with slopes; water closets exempt) - Vent sizing per the printed 906.2 rule (half the drain served, min 1-1/4", one size up over 40 ft) - Stack vent lengths per the printed Table 906.1; every result cites the code table used

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1. First observed Oct 16, 2026 · 4:59 PM $0.99