How to read an audiogram
Quick answer
An audiogram is a chart that plots the quietest sound a person could hear at each of several frequencies, with frequency in hertz across the horizontal axis and loudness in decibels hearing level down the vertical axis, so a lower point on the chart means a louder sound was needed. This page explains what the chart shows; it cannot tell any individual reader what their own results mean, and only a licensed audiologist can interpret a specific audiogram.
An audiogram looks intimidating mostly because of what is not explained on it: a grid of dots and letters with no legend printed on the page itself. The grid and the symbols are a genuine, long-standing clinical convention, though, and once the axes and symbols are explained the chart becomes fairly readable.
What this page will not do is tell anyone what their own audiogram means for them. Nothing on a web page can perform a hearing test or interpret a result, and a printed chart in someone's hand is a reason to ask their audiologist questions, not a reason to self-diagnose from home.
What do the two axes actually show?
Frequency, in hertz, runs left to right, from low-pitched sounds to high-pitched ones. Hearing level, in decibels, runs top to bottom, and this is the part that trips people up: the top of the chart is quiet and the bottom is loud, so a point plotted low on the chart means a louder sound was required before it was heard, which is the opposite of what "high" and "low" suggest intuitively. A standard audiogram tests seven frequencies, from 125 Hz up to 8000 Hz.
What do the symbols on the chart mean?
A red O marks the right ear tested through air conduction, and a blue X marks the left; different symbols mark masked testing and bone conduction.
| Symbol | Ear | Test route | Colour |
|---|---|---|---|
| O | Right | Air conduction, unmasked | Red |
| X | Left | Air conduction, unmasked | Blue |
| Triangle | Right | Air conduction, masked | Red |
| Square | Left | Air conduction, masked | Blue |
| < (left angle) | Right | Bone conduction, unmasked | Red |
| > (right angle) | Left | Bone conduction, unmasked | Blue |
What is the "speech banana," and why is it on the chart?
Low, voiced consonants sit at lower frequencies and comparatively higher loudness levels than sibilants like "s" and "th," which sit at higher frequencies and lower levels.
| Speech sound | Approx. frequency (Hz) | Approx. level (dB HL) |
|---|---|---|
| m, d, b, n | 250 | 30 |
| u, a, o vowels | 500 | 35 |
| i, e vowels | 1000 | 35 |
| k, g, ch, sh | 2000 | 30 |
| f, s, th | 4000 | 25 |
| s, th sibilants | 6000 | 25 |
The speech banana is the loosely banana-shaped region of the chart where the sounds of ordinary conversation fall, and it is the single most useful feature on an audiogram for a non-clinician to understand, because it shows which parts of speech sit above or below a plotted threshold.
Why can the same threshold be called "normal" on one chart and "mild" on another?
Because two different classifications exist and they genuinely disagree at the edges. The clinical convention used across routine United States audiology practice treats a pure tone average, the mean of the thresholds at 500, 1000 and 2000 Hz, from -10 to 25 dB HL as normal hearing for an adult. The World Health Organization's 2021 grades, applied to the better ear, set the boundary of "no impairment" lower, at 0 to 19 dB HL, meaning a threshold of 20 dB HL is normal on the first scale and mild on the second. Neither scale is wrong; they are simply different tools drawing the line in a different place.
These categories are applied to a pure tone average of 500, 1000 and 2000 Hz and are taught everywhere in the clinic, though no standards body publishes them.
| Category | Range (dB HL, PTA) |
|---|---|
| Normal hearing | -10 to 25 |
| Mild hearing loss | 26 to 40 |
| Moderate hearing loss | 41 to 55 |
| Moderately severe hearing loss | 56 to 70 |
| Severe hearing loss | 71 to 90 |
| Profound hearing loss | 91 to 120 |
The WHO grades apply to the better ear and set the "no impairment" boundary at 19 dB HL rather than 25, which is why the two scales can disagree on the same number.
| WHO grade | Range (dB HL, better ear) |
|---|---|
| No impairment | 0 to 19 |
| Mild | 20 to 34 |
| Moderate | 35 to 49 |
| Moderately severe | 50 to 64 |
| Severe | 65 to 79 |
| Profound | 80 to 94 |
| Complete or total | 95 to 120 |
What comes after an audiologist has reviewed the chart?
If amplification is discussed as an option, the audiologist's own findings, not the chart alone, decide whether that means a prescription device or whether a perceived mild to moderate result falls within what an OTC device such as MDHearing VOLT 4 or Jabra Enhance Select 700 is built for. The chart itself never makes that call; it is one input the professional interprets alongside everything else in the evaluation.
Common questions
- What is a pure tone average, and why does it matter?
- A pure tone average is the mean of the hearing thresholds measured at 500, 1000 and 2000 Hz, the three frequencies that carry most of ordinary speech. The clinical severity categories, normal through profound, are applied to this average rather than to any single frequency, so reading one high-frequency number off a chart and applying the category labels to it directly is a common way to reach a wrong-sounding conclusion.
- Why do the two ears sometimes have very different-looking plots?
- Because each ear is tested and plotted separately, using different symbols and colours specifically so the two results are never confused. It is entirely normal for the two ears to differ somewhat. A large or sudden difference between them is one of the specific reasons to contact a doctor rather than to self-manage, covered on our page about when to see an audiologist.
- Can I tell from my own audiogram whether I have hearing loss?
- Not reliably on your own, no. An audiogram is one part of a full evaluation that a licensed audiologist interprets alongside your history and other findings. This page explains what the axes and symbols show; it deliberately does not tell any reader what their own chart means, because that is a clinical judgment, not a lookup.
- What does it mean if my thresholds are plotted below the speech banana?
- It means that, at the tested loudness levels, sounds in that part of ordinary speech were not audible during the test. It does not by itself tell you the cause or what to do about it. Ask the professional who conducted your test what your specific results indicate for your own hearing and any next steps.
- Is bone conduction testing always part of an audiogram?
- Not always; it depends on what the initial air conduction results suggest and what the tester needs to investigate. Bone conduction testing, plotted with the angle-bracket symbols, helps a clinician determine whether a threshold shift originates in the outer or middle ear versus the inner ear, which is a distinction air conduction testing alone cannot make.
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Last updated 2026-09-17.