Bathroom Fan Sone Noise Calculator
Compare fan loudness and estimate combined sone level.
Enter your values
ⓘ Live results
Results
- Combined loudness
- 1 sones
- Comfort target
- <= 1 sones
- Meets target?
- Yes
- Approx dB(A)
- 30 dB(A) (rough)
Quick answer
For quiet bathrooms, look for fans rated 1.0-1.5 sones or less; multiple fans combine by roughly summing loudness, not simple addition of decibels.
Combined sones ~ sum of individual sone ratings (perceived loudness scale)
How to use the Bathroom Fan Sone Noise Calculator
- 1Look up each fan's sone rating from its spec sheet at rated CFM.
- 2Add sone ratings for fans operating in the same room.
- 3Compare the total to your comfort target and pick a quieter model if needed.
Worked example
Using the values the calculator loads with:
Inputs
- Fan 1 sone rating1.0 sones
- Fan 2 sone rating0 sones
- Comfort targetVery quiet (<=1.0 sone)
Results
- Combined loudness1 sones
- Comfort target<= 1 sones
- Meets target?Yes
- Approx dB(A)30 dB(A) (rough)
Frequently asked questions
Is a sone the same as decibels?
No — sones measure perceived loudness on a linear human-perception scale, while dB is a logarithmic sound-pressure scale.
Does higher CFM mean louder?
Not necessarily — larger, well-engineered fans running slower can move more air more quietly than small high-speed fans.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.