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Grease Trap Sizing Calculator

Size grease interceptors for commercial kitchens and food service establishments. Calculate capacity requirements based on fixture loads and code requirements.

System Configuration

Kitchen Fixtures

Kitchen Equipment

5 GPM, 4 DFU
8 GPM, 6 DFU
12 GPM, 8 DFU
4 GPM, 4 DFU
3 GPM, 2 DFU
1.5 GPM, 1 DFU

Food Preparation

2.5 GPM, 2 DFU
3 GPM, 2 DFU
2 GPM, 2 DFU
2 GPM, 1 DFU
4 GPM, 2 DFU

Cooking Equipment

2 GPM, 2 DFU
1 GPM, 1 DFU
0.5 GPM, 1 DFU
1 GPM, 1 DFU

How Grease Trap Sizing Works

Basic Sizing Formula

C = Q × T × S × F

C = Required Capacity (gallons)

Q = Flow Rate (GPM)

T = Retention Time (minutes)

S = Storage Factor (1 + storage %)

F = Flow Rate Multiplier (code/peak load)

Flow Rate Calculation

Q = Σ(fixture GPM × count)

• Sum of all fixture flow rates

• Adjusted by peak load factor

• Modified by establishment type

• Code requirements applied

Retention Time Guidelines

Gravity Units: 30 minutes minimum

Hydromechanical: 1-3 minutes typical

High Load: Consider longer retention

Code Requirements: May specify minimum

Interceptor Type Selection Guide

Gravity Interceptors

Best For: High flow rates, outdoor installation

Capacity: 500-2000 gallons typical

Maintenance: Monthly to quarterly

Installation: Requires significant space

Hydromechanical Units

Best For: Limited space, indoor use

Capacity: 20-75 GPM typical

Maintenance: Weekly to bi-weekly

Installation: Under-sink or in-floor

Professional Sizing Guidelines

Establishment Types

Fast Food: Higher grease output, frequent cleaning

Full Service: Moderate load, standard sizing

Cafeteria: High volume, peak load periods

Hotel/Hospital: Consistent load, 24/7 operation

Best Practices

• Size for maximum anticipated flow

• Consider future expansion needs

• Follow local code requirements

• Plan for regular maintenance access

• Include venting and monitoring points