Although many people talk about hearing loss in terms of percentage, it is not an appropriate or meaningful measure of hearing loss. Hearing is tested across many different frequencies or pitches, from low-pitched sounds like thunder all the way up to high pitches, like a whistle. It is very common to have more hearing loss at some frequencies than for others. Therefore, even if it were it possible to quantify hearing loss by percentage, for some people the percentage of hearing loss would be different at each test frequency, making it virtually meaningless when describing the overall hearing loss. Hearing loss is not measured in percentages, except in specific legal situations where decibels of hearing loss are converted via a recognized legal formula to create a "percentage of hearing loss" for legal purposes only.
The generally recognized categories of hearing loss are as follows:
Degree of Hearing loss Audiometric Thresholds
Normal hearing: 0 to 25 dB HL
Mild hearing loss 26 to 40 dB HL
Moderate hearing loss 41 to 70 dB HL
Severe hearing loss 71 to 90 dB HL
Profound hearing loss greater than 91 dB HL
Note that the term "audiometric threshold" refers to the lowest sound level that a person is able to hear at a specific frequency. The higher the threshold, the worse that person's hearing is.
It’s important to realize that the degree of hearing loss does not necessarily reflect the impact the hearing loss has on someone’s life. A mild hearing loss can be significantly handicapping for some people, while a moderate hearing loss may not have a great impact on someone else. An individual's lifestyle, support system, and feelings about the hearing loss strongly affect its impact, even more so than the clinical diagnosis.