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Grease Interceptor Size Estimator

Who it's for: Plumbing designers, commercial kitchen contractors, estimators, and facility teams.

Grease Interceptor Size Estimator helps plumbing designers, commercial kitchen contractors, estimators, and facility teams. turn kitchen type (light/medium/heavy), fixture flow and retention time, sizing method (flow x time or fixture-based) into recommended interceptor gallons, suggested standard size, method used summary without hiding the assumptions behind the result.

Calculator Inputs

Next Steps

  • Use consistent flow assumptions across related plumbing calculators to compare options cleanly.
  • Heavy-load kitchens can drive materially larger interceptor estimates than light-duty spaces.
  • Fixture-based mode is useful when sink geometry is known but peak flow is uncertain.

Worked Example

Example: enter realistic values for kitchen type (light/medium/heavy), fixture flow and retention time, review recommended interceptor gallons, suggested standard size, then compare the result with field conditions before using it for a material or equipment decision.

How This Calculator Works

Supports a flow-times-retention method and a fixture-volume method for quick planning comparisons. Applies kitchen load factor assumptions (light, medium, heavy) to adjust base volume. Maps estimated gallons to the nearest common standard interceptor size.

  • Supports a flow-times-retention method and a fixture-volume method for quick planning comparisons.
  • Applies kitchen load factor assumptions (light, medium, heavy) to adjust base volume.
  • Maps estimated gallons to the nearest common standard interceptor size.

Common Mistakes

  • Entering kitchen type (light/medium/heavy) in the wrong unit or using an unverified field estimate.
  • Reading recommended interceptor gallons without checking the assumptions listed on the page.
  • Skipping manufacturer data, local code, or field verification when the result affects final installation.

FAQ

Start with flow x retention for a quick estimate, then compare with fixture-based mode when sink geometry is available.

Kitchen type applies a factor to estimated volume so heavier grease loads produce larger recommended sizes.

No. This is a planning estimator only and local codes and authorities may require specific sizing procedures.

Manufacturers may use different assumptions, performance criteria, and approved sizing methods than this MVP estimator.

When to Call a Professional

Use a licensed plumbing professional when the Grease Interceptor Size Estimator result affects final sizing, drainage performance, equipment selection, or local code compliance.

Related Calculators

Fixture Flow Rate Calculator

Estimate total and diversified fixture flow demand in GPM so plumbing teams can plan supply sizing and evaluate expected peak usage patterns.

Pipe Size Calculator

Estimate nominal supply pipe size from fixture count, run length, and material assumptions to support quick planning before detailed code checks.

Conclusion

Use the Grease Interceptor Size Estimator result to understand recommended interceptor gallons, suggested standard size, method used summary, local verification warning from kitchen type (light/medium/heavy), fixture flow and retention time, sizing method (flow x time or fixture-based). Keep the input assumptions with the result so another person can reproduce the same estimate.

About This Calculator

About this calculator: Plumbing designers, commercial kitchen contractors, estimators, and facility teams.

Educational planning estimate. Verify final plumbing decisions against local code, product data, and site conditions.

Written by BuildCalcTools Team - Grease Interceptor Size Estimator methodology and field-use notes.

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