Phon to sone converter
Convert between phon, the loudness level, and sones, which scale the way people hear: twice the sones, twice as loud.
That's 2× as loud as a conversation, while busy traffic is 2× louder. That is a loudness of 8 sones.
What it means
How loud does it sound?
For steady sounds, using Stevens’ rule above 40 phon. Fan and appliance makers quote sones measured to ANSI/AHRI standards.
Every unit
That loudness on every scale
Learn
Three things worth knowing
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+10 phon = ×2 loud
50 phon is 2 sones, 60 phon 4, 70 phon 8. A 1-sone fan is very quiet, a 4-sone one is noisy.
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Stevens’ power law
Psychologist Stanley Smith Stevens proposed the sone in 1936 after asking listeners to judge “twice as loud”.
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Sones are not decibels
10 dB more is ten times the power but only twice the loudness. Sones measure what you hear, decibels the physics.
Shortcuts
Popular loudness conversions
Background
About phons and sones
The ear does not hear all frequencies equally, so loudness is measured against a 1 kHz tone: a sound has a loudness level of N phon if it seems as loud as a 1 kHz tone at N dB.
Phons are logarithmic. Sones are linear in what you hear: 1 sone is 40 phon, 2 sones (50 phon) sounds twice as loud, 4 sones (60 phon) four times. Bathroom fans are rated in sones.