Grease Trap Sizing Calculator

Size grease interceptors for commercial kitchens based on fixture flow rates, retention time, and load factors per PDI standards.

Flow per Fixture

GPM

Number of Fixtures

Retention Time

minutes

PDI G101: standard retention 1.5–2.5 minutes; heavy grease use (fryers) use 2–3 min; verify with AHJ

Load Factor

Tab to move between fields

Grease Trap Size

100 gallons

Cleaning Frequency

1 weeks

Total Flow Rate45 GPM

Grease Capacity25 gallons

How to Use This Calculator

Enter the flow rate per fixture (typically 20 GPM for a 3-compartment sink).
Enter the number of fixtures draining into the grease trap.
Set the retention time — 30 minutes is the PDI standard minimum for interceptors.
Adjust the load factor based on menu type (1.0 = light fare, 1.5 = heavy fry operation).
Review Grease Trap Size in gallons — use this to specify the interceptor on your drawings.
Note the Cleaning Frequency to schedule pumping service for code compliance.

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