How to read an audiogram chart
Quick answer
An audiogram plots frequency from 125 Hz to 8000 Hz across the horizontal axis and hearing level in decibels down the vertical axis, from about -10 dB HL at the top to around 120 dB HL at the bottom, so a mark lower on the chart means a louder sound was needed before it was heard. By long-standing convention, the right ear is plotted as a red circle (O) and the left ear as a blue cross (X).
An audiogram is the chart a hearing test produces, not the test itself. Each mark on it records the quietest tone a person could hear at one specific pitch, plotted against how loud that tone had to be. This page explains what every part of that chart shows and how the standard symbols work. It does not, and cannot, tell any individual reader what their own hearing is.
The symbols, axes and shading described below are the same in essentially every clinic, because they follow a long-standing convention in audiology rather than something each office invents for itself. Once the layout is familiar, a stranger's audiogram and a reader's own past one read the same way.
The two axes
Frequency runs left to right across the top, hearing level runs top to bottom on the side, and a mark lower on the page always means a louder sound was required.
| Axis | Range | What it means |
|---|---|---|
| Horizontal (X) | 125 Hz to 8000 Hz | Frequency, or pitch, of the test tone: low pitches on the left, high pitches on the right. |
| Vertical (Y) | -10 dB HL at the top to about 120 dB HL at the bottom | Hearing level: how loud a tone had to be before it was heard. Lower on the chart means a louder tone was needed. |
The seven frequencies a standard audiogram tests
Only 500, 1000 and 2000 Hz are averaged into the pure tone average that the hearing loss severity categories are applied to.
| Frequency (Hz) | Used in the pure tone average? |
|---|---|
| 125 | No |
| 250 | No |
| 500 | Yes |
| 1000 | Yes |
| 2000 | Yes |
| 4000 | No |
| 8000 | No |
Reading the symbols
Right ear results are always plotted in red, left ear results always in blue, regardless of which clinic performed the test.
| Symbol | Ear | Test route | Colour |
|---|---|---|---|
| O | Right | Air conduction, unmasked | Red |
| X | Left | Air conduction, unmasked | Blue |
| △ | Right | Air conduction, masked | Red |
| □ | Left | Air conduction, masked | Blue |
| < | Right | Bone conduction, unmasked | Red |
| > | Left | Bone conduction, unmasked | Blue |
The speech banana and the pure tone average
The banana-shaped region runs from low, quiet consonants like m and d up near 250 Hz to the quietest high-frequency sounds like s and th out past 6000 Hz.
| Speech sounds | Frequency (Hz) | Level (dB HL) | Sound type |
|---|---|---|---|
| m, d, b, n | 250 | 30 | Low-frequency voiced sounds |
| u, a, o vowels | 500 | 35 | Vowels |
| i, e vowels | 1000 | 35 | Vowels |
| k, g, ch, sh | 2000 | 30 | Mid to high consonants |
| f, s, th | 4000 | 25 | High-frequency consonants |
| s, th sibilants | 6000 | 25 | The quietest consonants |
Working out a pure tone average
The pure tone average is the mean of the thresholds at 500, 1000 and 2000 Hz, the three frequencies marked "Yes" in the table above, and it is the figure the hearing loss severity categories are applied to. As a worked example only, not a real result: thresholds of 30 dB HL at 500 Hz, 35 dB HL at 1000 Hz and 40 dB HL at 2000 Hz average to (30 + 35 + 40) divided by 3, which is 35 dB HL. Applying a severity category to a single high-frequency threshold instead of this three-frequency average is one of the most common ways an audiogram gets misread. Once an actual pure tone average comes from a real test, it is the figure used to judge whether the mild to moderate range an over the counter device such as Jabra Enhance Select 700 or Audien Atom One is built for is even the right category to shop in.
Common questions
- What do the axes on an audiogram show?
- The horizontal axis shows frequency, or pitch, from 125 Hz on the left to 8000 Hz on the right. The vertical axis shows hearing level in decibels, running from about -10 dB HL at the top down to around 120 dB HL at the bottom. Because the scale runs top to bottom this way, a mark lower on the page always means a louder tone was needed before it was heard.
- What is the speech banana on an audiogram?
- It is the banana-shaped region on the chart where the sounds of ordinary conversational speech typically fall, running from low consonants like m and d around 250 Hz up to quiet high-frequency sounds like s and th out past 6000 Hz. It is useful because it shows, at a glance, which speech sounds sat above or below a plotted threshold during the test.
- What is the difference between the red circle and the blue X on an audiogram?
- By long-standing convention, the right ear is always plotted as a red circle (O) and the left ear as a blue cross (X), for unmasked air conduction testing. Masked air conduction uses a red triangle for the right ear and a blue square for the left, and bone conduction uses a red "less than" symbol for the right ear and a blue "greater than" symbol for the left.
- What is a pure tone average and how is it calculated?
- A pure tone average is the mean of the hearing thresholds measured at 500, 1000 and 2000 Hz, the three frequencies where most speech energy sits. It is calculated by adding the three thresholds and dividing by three. The clinical and WHO hearing loss severity categories are applied to this three-frequency average, not to any single frequency on its own.
- Why does an audiogram use separate symbols for masked testing?
- Masking plays noise into the ear that is not currently being tested, which stops a loud tone in one ear from being picked up by the other ear and recorded as a false result for the wrong side. A masked triangle or square on the chart tells a reader that this extra step was needed to isolate the ear actually being measured.
- Can I read my own hearing loss from a picture of an audiogram at home?
- Understanding what the symbols and axes mean, yes; that is what this page explains. Producing an actual audiogram, no. A real chart comes from a calibrated hearing test performed by a licensed audiologist, and no web page or phone app can generate or substitute for that measurement. This page can only explain a chart that already exists.
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Last updated 2026-09-17.