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HUD   >   Program Offices   >   Community Planning and Development   >   Environment   >   DNL Calculator

Site DNL Calculator


For more information on using the noise calculator, to access the user guidebook, or send comments, please visit the following page:
Day/Night Noise Level Electronic Assessment Tool


  • To display the Road and/or Rail DNL calculator(s), click on the "Add Road Source" and/or "Add Rail Source" button(s) below.
  • All Road and Rail input values must be positive non-decimal numbers.
  • All Road and/or Rail DNL value(s) must be calculated separately before calculating the Site DNL.
  • All checkboxes that apply must be checked for vehicles and trains in the tables' headers.
  • Note #1: Tooltips, containing field specific information, have been added in this tool and may be accessed by hovering over all the respective data fields (site identification, roadway and railway assessment, DNL calculation results, roadway and railway input variables) with the mouse.
  • Note #2: DNL Calculator assumes roadway data is always entered.
Site ID
Record Date
User's Name

Airport Noise Level
Loud Impulse Sounds?
Yes No
Combined DNL for all
Road and Rail sources
Combined DNL including Airport
Site DNL with Loud Impulse Sound
Mitigation Options

If your site DNL is in Excess of 65 decibels, your options are:

  • No Action Alternative
    Cancel the project at this location DNL Calculator
  • Other Reasonable Alternatives
    Choose an alternate site DNL Calculator
  • Mitigation
    • Contact your Field or Regional Enviornmental Officer - Environmental Contacts
    • Increase mitigation in the building walls (only effective if no outdoor, noise sensitive areas).
    • Reconfigure the site plan to increase the distance between the noise source and noise-sensitive uses DNL Calculator
    • Incorporate natural or man-made barriers. See The Noise Guidebook
    • Construct noise barrier. See the Barrier Performance Module