The lines, symbols and numbers on your hearing test report, decoded in plain language, with no jargon.
Quick answer
An audiogram plots pitch (frequency in Hz) on the horizontal axis and loudness (dB HL) on the vertical axis. O marks the right ear, X marks the left. Thresholds between 0 and 25 dB HL are normal; 26–40 dB is mild loss, 41–55 dB moderate, 56–70 dB moderately severe, 71–90 dB severe, and 91 dB or worse is profound. A line sloping toward the bottom-right indicates high-frequency hearing loss.
Key takeaways
- X = left ear, O = right ear. Lower on the chart means louder was needed.
- Speech frequencies sit between 500 Hz and 4,000 Hz.
- Normal adult hearing = 0–25 dB HL across all tested frequencies.
- High-frequency loss is the most common pattern with age and noise exposure.
- Mild loss can still deserve hearing aids when it affects work, safety or family life.
An audiogram is a simple line graph. Once you understand the axes, you can read yours in about three minutes.
The two axes
The horizontal axis is frequency (pitch) measured in Hertz, from low bass on the left (250 Hz) to high treble on the right (8000 Hz). The vertical axis is loudness in decibels, with the softest sounds at the top (0 dB) and loudest at the bottom (120 dB).
The symbols
- O = right ear (usually red)
- X = left ear (usually blue)
- The lower a symbol sits on the graph, the louder the sound needed for you to hear that frequency
The severity bands
- 0–25 dB: Normal hearing
- 26–40 dB: Mild loss
- 41–55 dB: Moderate loss
- 56–70 dB: Moderately severe loss
- 71–90 dB: Severe loss
- 91+ dB: Profound loss
What does a normal PTA graph look like?
On a normal audiogram every O and X sits at or above the 25 dB line, from the low pitches on the left (250 Hz) to the high pitches on the right (8000 Hz). The two ears sit close to each other, and the bone-conduction marks (< > or [ ]) overlap the air-conduction marks. A normal graph does not rule out every problem: trouble following speech in noise needs its own tests, which our PTA symbols and chart guide explains.
The shape tells the story
A flat line means loss is even across frequencies. A downward slope (common with age or noise exposure) means high frequencies are affected first, which is why S, F and TH sounds fade before vowels do.
| Pattern on the graph | What it usually means | What usually happens next |
|---|---|---|
| Both ears slope down towards the high pitches, air and bone marks together | Age-related (sensorineural) hearing loss, the most common pattern after 60 | Hearing aids if daily life is affected; see age-related hearing loss |
| A dip around 4000 Hz that recovers at 8000 Hz | A noise notch, typical of long-term exposure to loud noise | Hearing protection, monitoring, and aids if speech is affected |
| Air marks lower than bone marks (an air–bone gap) | A conductive problem in the outer or middle ear: wax, fluid, a perforation or otosclerosis | ENT review first; often treatable medically or surgically |
| A bone-conduction dip around 2000 Hz together with an air–bone gap | Can suggest otosclerosis (a 'Carhart notch') | ENT review; see otosclerosis: surgery or hearing aids |
| Worse in the low pitches, rising towards the right | Low-frequency loss, sometimes seen with Ménière's disease | ENT review, especially with dizziness or hearing that fluctuates |
| One ear much worse than the other | Asymmetric hearing loss | ENT review before any hearing aid, to rule out a medical cause |
| A flat line across all pitches | An even loss at every pitch, with several possible causes | Depends on the degree; your audiologist explains |
A worked example
Say the right ear shows O marks at 15–20 dB from 250 to 1000 Hz, sloping down to 50 dB at 4000 Hz, with the bone-conduction marks sitting on top of them. Reading left to right: normal hearing for low pitches, then a moderate loss for the highest pitches, and no air–bone gap. That points to a sensorineural, high-frequency loss, the typical age-related pattern. In daily life vowels sound fine but consonants like s, f and th get lost, so speech seems loud enough yet unclear.
What is the pure tone average on my report?
Many reports print one number per ear, such as "PTA 38 dB HL". That is the pure tone average: the mean of your thresholds at the main speech frequencies, usually 500, 1000 and 2000 Hz, sometimes with 4000 Hz added. Compare it with the severity bands above. Because it averages, it can hide a steep high-frequency loss, so always look at the full graph too. Our PTA chart guide shows how it is worked out.
When the graph means a doctor first
See an ENT doctor before discussing hearing aids if your graph shows a sudden change, one ear much worse than the other, or an air–bone gap. These patterns can have medical causes that need treatment. A hearing aid manages hearing loss; it does not treat its cause.
Bring your audiogram to any Prudent Hearing clinic and we'll walk through it with you at no cost.
Continue reading
Frequently asked questions
How do you read an audiogram?
The horizontal axis shows pitch (frequency in Hz, low on the left, high on the right); the vertical axis shows loudness (dB HL, quiet at the top, loud at the bottom). O marks the right ear, X marks the left. The lower a mark sits, the louder that pitch has to be for you to hear it, so lines that drop toward the bottom-right mean high-frequency hearing loss.
What is a normal audiogram result?
Thresholds between 0 and 25 dB HL across 250 Hz–8,000 Hz are considered normal for adults. 26–40 dB HL is mild loss, 41–55 dB HL moderate, 56–70 dB HL moderately severe, 71–90 dB HL severe, and 91 dB HL or worse is profound.
Why is my audiogram worse on high frequencies?
Age and noise damage the fragile hair cells in the base of the cochlea first: the ones that detect high frequencies (2–8 kHz). This is why consonants like S, F, TH and SH become unclear long before vowels, so speech sounds muffled but not quiet.
Do I need hearing aids if my audiogram shows mild loss?
Not always. The decision depends on how much day-to-day difficulty you have, whether you work in demanding listening environments, and whether family members notice. Modern hearing aids are strongly recommended for mild loss when it affects work, safety or social life, because early treatment protects speech understanding long-term.
What does a dip at 4000 Hz on my audiogram mean?
A dip around 4000 Hz that recovers at 8000 Hz is called a noise notch. It is the typical pattern of hearing damage from long-term loud noise. It is permanent, so protect your ears from further noise and have your hearing monitored; aids help if speech has become harder to follow.
What is an air-bone gap on a PTA graph?
It is the distance between the air-conduction marks (O and X) and the bone-conduction marks (< > or [ ]) at the same pitch. A real gap means sound is blocked before it reaches the inner ear, for example by wax, fluid, a perforation or otosclerosis. Many of these causes are treatable, so an ENT review comes first.
Sources & further reading
We cross-checked this article against the following authoritative sources. Guidance and figures reflect the most recent public guidance available at the time of last review (October 2026). Clinical review by the Prudent Hearing clinical team.
- Understanding your audiogram (American Speech-Language-Hearing Association (ASHA))
- Deafness and hearing loss (World Health Organization (WHO))
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