Normal: <20dB HL
Most adults' experience in a quiet environment: no problem hearing sounds
Most adults' experience in a noisy environment: no or almost no problem hearing sounds
Mild: 20~<35dB HL
Most adults' experience in a quiet environment: no problem talking
Most adults' experience in a noisy environment: may not be able to hear the conversation clearly
Moderate: 35~<50dB HL
Most adults' experience in a quiet environment: may not be able to hear the conversation clearly
Most adults' experience in a noisy environment: difficulty in talking
Moderate to severe: 50~<65dB HL
Most adults' experience in a quiet environment: difficulty in talking, can communicate normally after increasing the volume
Most adults' experience in a noisy environment: most conversations are difficult
Severe: 65~<80dB HL
Most adults' experience in a quiet environment: most of the conversation cannot be heard, even if the volume is increased, it cannot be improved
Most adults' experience in a noisy environment: very difficult to participate in the conversation
Extremely severe: 80~<95dB HL
Experience of most adults in quiet environment: extremely difficult to hear sounds
Experience of most adults in noisy environment: cannot hear conversations
Total deafness: ≥95dB HL
Experience of most adults in quiet environment: cannot hear speech and most environmental sounds
Experience of most adults in noisy environment: cannot hear speech and most environmental sounds
Unilateral deafness: good ear less than 20dB HL, bad ear ≥35dB HL
Experience of most adults in quiet environment: no problem unless the sound is close to the worse ear, there may be difficulty in sound localization
Experience of most adults in noisy environment: may have difficulty in speech, conversation and sound source localization
Google
Amazon