Estimate how much quieter a sound becomes after noise reduction. Enter the starting sound level and reduction amount to calculate the final dB level, energy reduction, transmitted energy, and reduction category.
Final level mode:
Enter a starting noise level and a dB reduction. The calculator subtracts the reduction from the starting level.
Before and after mode:
Enter the original and final sound levels. The calculator finds the difference in dB.
Energy percent mode:
Enter the percent of sound energy that remains. The calculator converts that percent into dB reduction.
A noise reduction calculator helps estimate how much a sound level changes after adding a barrier, enclosure, treatment, silencer, distance change, door seal, acoustic panel, or other noise-control step.
This calculator gives a simplified estimate. Real results may change with frequency, reflections, gaps, wall construction, measurement position, background noise, and flanking paths.
Common formulas used by this calculator:
Subtract the final sound level from the starting sound level. For example, 85 dB reduced to 65 dB is a 20 dB noise reduction.
A 10 dB reduction means about 90% less sound energy remains, although perceived loudness depends on frequency, listener, and context.
No. Noise reduction can come from blocking, distance, barriers, enclosures, silencers, or absorption. Absorption mainly reduces reflections inside a space.
Sound can leak through gaps, doors, windows, vents, outlets, ceiling paths, floor paths, framing, and other flanking paths.