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LSTN Editorial Team · Editorially overseen by Dan McCoy
Adult hearing is classified as normal when your thresholds, the quietest sounds you can detect, fall between 0 and 25 dB HL at every tested frequency. That standard doesn't change as you get older. Thresholds do tend to rise with age, but 'typical for your age' and 'normal hearing' are two different claims, and the gap between them is where a lot of untreated hearing loss hides.
A hearing threshold is the softest sound you can detect at a specific frequency, measured in decibels hearing level (dB HL). Thresholds from 0 to 25 dB HL are classified as normal for adults. Beyond that, hearing loss is graded by severity: mild (26-40 dB), moderate (41-55 dB), moderately severe (56-70 dB), severe (71-90 dB), and profound (91 dB and above).
A threshold of 0 dB HL doesn't mean silence. The scale is calibrated so that 0 represents the average softest sound young adults with healthy hearing can detect at each frequency. Healthy ears often test between 0 and 10 dB HL, and some people score slightly below 0.
The numbers that matter most sit in the speech range, roughly 500 to 4,000 Hz. Elevated thresholds there affect conversation directly. Elevated thresholds at 6,000 or 8,000 Hz matter too, but they usually show up as trouble with birdsong, alarms, and consonant clarity rather than overall volume.
Age-related hearing loss (presbycusis) follows a consistent pattern. The hair cells that detect high frequencies wear out first, so thresholds at 4,000 to 8,000 Hz begin rising years before anything changes in the speech range. Most people notice nothing at this stage because vowels and overall loudness are untouched.
The shift accumulates steadily. According to the NIDCD, about one in three adults between 65 and 74 has hearing loss, and nearly half of adults over 75 do. For most people the change becomes measurable somewhere in their 50s and 60s, high frequencies first.
From the inside, that trajectory feels like this: conversations in quiet still work, but restaurants get harder, consonants blur ('ship' becomes 'hip'), and the TV creeps louder. The speech frequencies are often still classified as normal while the high frequencies have already moved into mild or moderate loss.
Clinical classification doesn't grade on an age curve. A 40 dB threshold is moderate hearing loss whether you're 35 or 75. What changes with age is how common elevated thresholds are, and common is not the same as harmless.
The confusion comes from two different standards. Statistical norms, like the ISO 7029 standard that tracks typical thresholds by age and sex, describe what the average ear does over time. The functional standard, 0-25 dB HL, describes what an ear needs to follow speech comfortably. A 70-year-old with thresholds typical for 70 may still be missing a meaningful share of everyday conversation.
In the clinics I managed, 'my doctor said it's just normal aging' was one of the most common lines we heard from new patients. The audiologists on my team treated it as a flag rather than a reassurance, because it usually meant a real, measurable loss had been noticed and then waved off without a plan.
Untreated loss doesn't stay contained, either. It shows up as listening fatigue, skipped gatherings, and strained conversations at home long before it looks like a medical problem.
Two benchmarks are worth keeping. First: any threshold above 25 dB HL in the speech range, especially alongside real-world difficulty, justifies a full hearing evaluation. Second: a sudden drop in hearing, particularly in one ear, is a medical emergency. Sudden sensorineural hearing loss has a treatment window measured in days, so same-day care matters.
A full evaluation with an audiologist measures thresholds across the complete frequency range, in each ear, with bone conduction testing to identify where the problem sits. That's the gold standard, and nothing online replaces it.
If you're not ready for an appointment, you can still get a starting point. LSTN's free hearing test screens your thresholds from 500 to 4,000 Hz in about 10 seconds and classifies each ear from normal to severe. It's a screening, not a diagnosis, but it turns 'I think something's off' into a number you can act on. And if you already have an audiogram from a clinic, the Audiogram Review tool explains what your thresholds mean in plain English.
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