How to read an audiogram

An audiogram is the chart a hearing test produces. It answers one question over and over: what is the quietest sound this ear can hear at this pitch? Each mark is one answer — a threshold.

The two axes

Across the bottom is pitch, in hertz (Hz), from low on the left to high on the right. The standard test frequencies are 250, 500, 1000, 2000, 4000, and 8000 Hz, with 3000 and 6000 Hz often added in between — those half-octave columns are the dashed ones.

Down the side is loudness, in decibels hearing level (dB HL). The scale is upside down compared with most charts: quiet is at the top, loud is at the bottom. 0 dB HL is the average threshold of young adults with typical hearing, at every frequency. A mark further down the chart means the sound had to be made louder before it was heard — so lower on the chart means more hearing loss.

Symbols

The layout isn't a house style; it follows the international standard for audiometry, ISO 8253-1,¹ which is why an audiogram from a clinic in another country still reads the same way. Every chart on this site is drawn to it: the same axes, the same marks, the same colors.

By convention, each ear gets its own mark and color:

• O in red is the right ear.
• X in blue is the left ear.

When the two ears match, the lines sit on top of each other. When they don't, the gap between them is itself information: hearing that differs noticeably between ears is worth having looked at.

How much is a lot?

Clinicians group thresholds into degrees. This site uses the scale most U.S. audiologists use, from the American Speech-Language-Hearing Association (ASHA),² shown as colored bands on every audiogram:

Other countries often use the World Health Organization's grades,³ which draw the lines a little differently, so the same audiogram can get a different label elsewhere.

The speech banana

Everyday speech occupies a curved region in the middle of the chart, nicknamed the speech banana. Vowels sit low and to the left — low-pitched and relatively loud. Consonants like s, f, and th sit high and to the right — high-pitched and quiet.

Anything above a person's threshold line is audible to them; anything below it isn't. Turn on Speech sounds in the chart above and the letters the ear can't reach grey out. That is why so many people with high-frequency loss say they can hear people talking but can't understand them: the vowels come through, the consonants don't.

Common shapes

• Sloping down to the right — more loss at high pitches than low. The most common shape overall, whether the loss is congenital, noise-related, or age-related.
• A notch around 4 kHz with recovery at 8 kHz — the signature of noise exposure.
• A U-shape, or "cookie bite" — most loss in the middle pitches, often inherited.
• Flat — similar loss everywhere, common in conductive loss.
• One ear far worse — asymmetric; a sudden change like this needs prompt medical attention.

Every profile in the simulator is one of these shapes. The profile gallery lets you look at them side by side.