An audiogram is a chart that maps your hearing ability across different pitches and volumes. It’s the primary tool audiologists use to determine whether you have hearing loss, how severe it is, and what type it is. If you’ve had a hearing test or been told you need one, the audiogram is the result you’ll walk away with.
What the Chart Actually Shows
An audiogram is a graph with two axes. The horizontal axis (left to right) shows pitch, measured in Hertz (Hz), typically ranging from 250 Hz on the left (low-pitched sounds, like a rumbling engine) to 8,000 Hz on the right (high-pitched sounds, like a bird chirping). Human speech falls mostly between 250 and 6,000 Hz, which is why this range gets the most attention.
The vertical axis (top to bottom) shows volume, measured in decibels (dB), usually from 0 dB at the top to 110 dB at the bottom. This is counterintuitive at first: the top of the chart represents very soft sounds, and the bottom represents very loud ones. So a mark near the top of the graph means you can hear soft sounds at that pitch, which is good. Marks that fall lower on the chart mean you needed more volume to detect the sound.
Symbols and Colors on an Audiogram
Each ear gets its own set of marks. The right ear is plotted with red circles (O), and the left ear with blue crosses (X). When you see these connected by lines, you’re looking at your hearing threshold for each ear across different pitches. The threshold is the softest sound you could reliably detect.
You may also see bracket-like symbols: angle brackets (< >) for the right ear and square brackets ([ ]) for the left. These represent bone conduction results, which test how sound travels through the bones of your skull directly to the inner ear, bypassing the ear canal and eardrum. The difference between your air conduction results (the O and X marks) and your bone conduction results matters for diagnosis, which is covered below.
What Happens During the Test
The test itself is straightforward. You sit in a soundproof booth wearing headphones or earbuds. The audiologist controls the equipment from an adjacent room, watching you through a window. Tones are played one at a time into one ear, starting at a pitch of 1,000 Hz, which is roughly the pitch of a higher-pitched speaking voice.
The audiologist begins at a volume you can hear easily, then gradually makes it softer. Each time you hear a tone, you press a button, raise your hand, or say “yes.” When you stop responding, they increase the volume slightly and try again. This back-and-forth narrows in on the exact threshold: the quietest level at which you can detect the sound at least half the time. The process repeats across pitches, working through 1,000, 2,000, 3,000, 4,000, 6,000, and 8,000 Hz, then circling back to recheck 1,000 Hz before testing 500 and 250 Hz.
For young children who can’t press a button reliably, audiologists use adapted techniques. One approach rewards the child with a visual display (like a lit-up toy) when they respond correctly. Another turns the process into a game with toys, so the child learns to perform a specific action every time they hear a sound. The whole test typically takes 15 to 30 minutes.
Degrees of Hearing Loss
Where your marks fall on the volume axis tells you the degree of hearing loss. The threshold for normal hearing was recently lowered from 25 dB to 20 dB. Here’s how the current classification from the Global Burden of Disease Expert Group breaks down:
- Normal hearing (below 20 dB): You can follow conversations even in noisy environments without much trouble.
- Mild hearing loss (20 to 34 dB): Quiet settings feel fine, but you may struggle to follow conversations in background noise.
- Moderate hearing loss (35 to 49 dB): You may have difficulty hearing a normal speaking voice, even in a quiet room. Group conversations become noticeably harder.
- Severe hearing loss (65 to 79 dB): You can hear loud speech directly in your ear but following a conversation, especially with background noise, is very difficult.
- Profound hearing loss (80 dB and above): Speech is largely inaudible. At 95 dB and above, even loud environmental sounds may not register.
These numbers represent an average across key frequencies. It’s common to have normal hearing in lower pitches but moderate loss in higher ones, which is why the shape of the line on your audiogram matters as much as the overall number.
Types of Hearing Loss an Audiogram Reveals
This is where the two sets of symbols become important. Air conduction tests (the O and X marks) measure how sound travels through your entire hearing system: the ear canal, eardrum, middle ear bones, and inner ear. Bone conduction tests (the bracket symbols) send vibrations through your skull directly to the inner ear, skipping the outer and middle ear entirely.
When both air and bone conduction results are equally reduced, the problem is in the inner ear or the hearing nerve. This is called sensorineural hearing loss, and it’s the most common type, often caused by aging or noise exposure. The audiogram will show both sets of symbols falling in roughly the same position.
When air conduction is worse than bone conduction, something is blocking or disrupting sound before it reaches the inner ear. This gap between the two measurements is called an air-bone gap, and it points to conductive hearing loss. Common causes include fluid in the middle ear, a perforated eardrum, or problems with the tiny bones that transmit sound. Air-bone gaps can range from small to as large as 50 or 60 dB, and they may affect all frequencies or concentrate in the lower pitches.
Some people have both types at once, called mixed hearing loss. On their audiogram, bone conduction results are reduced (indicating inner ear involvement), but air conduction results are even worse (indicating an additional blockage or middle ear problem on top of it).
Common Audiogram Patterns
The shape of the line on your audiogram tells a story. A flat line across all pitches, sitting within the normal range at the top of the chart, means your hearing is healthy. A line that slopes downward from left to right, with good hearing in the low pitches but progressively worse hearing in the high pitches, is the classic pattern of age-related hearing loss or noise damage. This is the most common pattern audiologists see in adults.
A line that dips sharply at one specific frequency, often around 4,000 Hz, and then partially recovers at higher pitches creates a “notch.” This pattern is characteristic of noise-induced hearing loss from things like loud machinery, concerts, or firearms. A line that’s relatively flat but sitting well below the normal range across all frequencies suggests a more uniform loss, which can occur with certain medical conditions.
When to Get Your Hearing Tested
The World Health Organization recommends routine hearing screening starting at age 50. If your results come back normal, rescreening every five years is reasonable between ages 50 and 65. After 65, testing every one to three years makes more sense, since age-related changes can accelerate. Outside of these age-based guidelines, anyone who works around loud noise, notices difficulty following conversations, or experiences ringing in their ears has good reason to get a baseline audiogram sooner.
Your audiogram results become part of your medical record and serve as a reference point for tracking changes over time. A single audiogram tells you where your hearing stands today. Comparing audiograms from different years reveals whether your hearing is stable or shifting, and how quickly.