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Grease Trap Sizing Calculator (PDI-G101 Method)

Calculate the required grease trap capacity for a commercial kitchen, based on flow rate, retention time, and storage factor.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax

Required grease trap capacity

134.73 gal

Check your inputs

Flow rate and storage factor depend on the specific fixtures connected (per PDI-G101 fixture flow rate tables) and food service type — confirm against your local plumbing code's grease interceptor sizing requirements.

For the dimensions entered, expect a required grease trap capacity of 510 L. Moderate confidence — sound arithmetic, but allow for the variation any real site introduces. Set for United States against IRC 2024. The market selector changes both the units and the code cited.

Estimated cost — your price

This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • PDI-G101 method: required grease trap capacity = flow rate × retention time × storage factor, the standard plumbing industry method for sizing hydromechanical grease interceptors for commercial kitchen fixtures

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Frequently asked questions

What is the PDI-G101 method?
PDI-G101 is the standard plumbing industry method for sizing hydromechanical grease interceptors for commercial kitchen fixtures, using the formula required capacity = flow rate × retention time × storage factor.
Where does the flow rate value come from?
Flow rate should come from the PDI-G101 fixture flow rate tables, totaled across the specific fixtures (sinks, dishwashers, etc.) connected to the interceptor — confirm the correct per-fixture values for your equipment.
Can I rely on this result alone for a permit-ready grease interceptor size?
No — flow rate and storage factor depend on the specific connected fixtures and food service type. Always confirm the required capacity against your local plumbing code's grease interceptor sizing requirements before selecting equipment.