Grease Trap Sizing Calculator

Grease is lighter than water, and a grease trap is a pause for that fact to matter: warm, greasy washwater slows, cools, and the fat floats to the top where it cannot clog the building drain or the municipal line.

Grease Trap Sizing Calculator estimates the interceptor capacity you need from sink volume, dishwasher flow and fixture load, using common kitchen-sizing methods.

• Sink-volume method: 1.5x bowl volume alone, 2.5x with a dishwasher.
• Fixture-flow method: Peak GPM held for one hour.
• Two methods compared: take the larger practical number.
• Gallons and liters: plus nearest stock size.
• Export: Copy or download the report.

1. Pick a sizing method.
2. Sink method: count bowls and enter one bowl’s interior L x W x D in inches; add dishwasher GPM if present.
3. Flow method: enter the total fixture flow in GPM.
4. Read the recommended capacity and nearest stock size.

Example - Small café. One double-compartment sink, 16x14x12 in bowls: volume 2 x (16x14x12/231) = ~23 gal. With a 3 GPM dishwasher, recommended = 23 x 2.5 = ~58 gal, so an 75 gal or listed interceptor depending on local size steps.

• Permit-stage numbers: capacity before equipment is bought.
• Compares both styles: PDI-style and flow-style answers.
• Liters included: useful where metric permits reign.
• Free and private: no uploads, no logging.