A normal audiogram shows all hearing thresholds at or above the 20 dB line across every frequency tested, with both ears producing nearly identical results. On the graph, this looks like a relatively flat line running along the top portion of the chart. If you’ve just had a hearing test or you’re trying to make sense of one, here’s how to read it and what “normal” actually means in concrete terms.
How an Audiogram Is Set Up
An audiogram is a graph with two axes. The horizontal axis (left to right) shows frequency in Hertz, representing pitch. Standard tests measure eight frequencies: 250, 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz. Low-pitched sounds like a rumbling engine sit on the left side; high-pitched sounds like birds chirping sit on the right.
The vertical axis shows intensity in decibels Hearing Level (dB HL), representing volume. Here’s where audiograms can be confusing: the scale is inverted. Quiet sounds are at the top (starting around -10 dB), and loud sounds are at the bottom (going down to 100 or 120 dB). So better hearing appears higher on the chart, and worse hearing appears lower.
Each point plotted on the graph represents the quietest sound you could detect at that specific pitch at least 50% of the time. These points are connected with lines to create a visual picture of your hearing across the full range of tested frequencies.
Symbols for Each Ear
The right ear is marked with circles (O), and the left ear is marked with crosses (X). These are connected by lines, typically red for the right ear and blue for the left. These symbols represent air conduction testing, which is done through traditional headphones and measures how sound travels through the entire hearing pathway, from the outer ear through the middle ear to the inner ear.
You may also see a second set of symbols representing bone conduction testing, where a small vibrating device is placed behind the ear. Bone conduction bypasses the outer and middle ear and sends sound directly to the inner ear. In a normal audiogram, the air conduction and bone conduction results land at essentially the same level, because every part of the hearing system is working properly. When there’s a gap between the two, it suggests a problem in the outer or middle ear specifically.
What “Normal” Looks Like on the Chart
For adults, normal hearing is defined as thresholds of 20 dB HL or better at every frequency. The World Health Organization uses this same cutoff: anyone who can hear at 20 dB or better in both ears is considered to have normal hearing. Some clinical guidelines use 25 dB as the boundary, particularly when averaging across the speech frequencies. In practical terms, if all your plotted points sit between -10 and 20 dB on the chart, your hearing falls within the normal range.
For children, the standard is stricter. Normal hearing in kids is defined as thresholds between -10 and 15 dB at all frequencies. Children need slightly sharper hearing because they’re still developing language and rely heavily on picking up subtle speech sounds in noisy environments like classrooms.
On the graph itself, a normal result looks like two lines (one for each ear) running fairly flat across the top portion of the audiogram. The lines won’t be perfectly straight. Small dips and rises of 5 to 10 dB between frequencies are common and don’t indicate a problem. What matters is that every point stays above that 20 dB line.
Both Ears Should Look Similar
A normal audiogram is symmetrical, meaning the severity and shape of hearing are the same in each ear. The O line and X line should track closely together across all frequencies. When one ear shows noticeably different thresholds from the other, that’s called asymmetrical hearing, and it typically warrants further investigation even if both ears technically fall within the normal range.
The Speech Banana and Why It Matters
Many audiograms include a banana-shaped shaded region in the middle of the chart called the “speech banana.” This area represents the range of pitches and volumes where most speech sounds occur. It spans roughly 250 to 6000 Hz in frequency, with its center sitting around 33 to 58 dB HL depending on the source. Normal conversational speech at about an arm’s length away registers at approximately 57 dB in sound pressure.
The speech banana is a quick visual check. If your hearing thresholds are plotted well above the banana, you can hear everything within normal conversation comfortably. If your thresholds dip into or below the banana at certain frequencies, those specific speech sounds become harder to catch. For instance, a dip at the higher frequencies (4000 to 8000 Hz) might mean you struggle with consonants like “s,” “f,” and “th,” even though you hear vowels and lower-pitched sounds just fine.
Common Patterns That Aren’t Normal
Knowing what normal looks like also helps you spot what isn’t. A few common abnormal patterns are worth recognizing:
- High-frequency slope: Thresholds are normal at 250 to 1000 Hz but drop off at 2000 Hz and above. This is the most common pattern in age-related hearing loss and noise exposure. On the audiogram, the line angles downward from left to right.
- Noise notch: A sharp dip specifically at 4000 Hz, with recovery at 8000 Hz. This V-shaped notch is a classic signature of noise-induced hearing loss.
- Flat loss: Thresholds are equally reduced across all frequencies, creating a line that’s still flat but shifted downward on the chart. This can indicate certain middle ear conditions or other causes.
- Asymmetric results: One ear shows significantly worse thresholds than the other. Even if the better ear is normal, a meaningful difference between the two sides is something audiologists take seriously.
How to Read Your Own Results
If you’re looking at your audiogram, start by finding the O and X symbols. Check whether all of them sit at 20 dB or higher on the chart (remember, “higher” means closer to the top because the scale is flipped). Then compare the two ears. If both lines are hovering near the top and tracking close to each other, your hearing is normal.
Pay particular attention to the frequencies between 500 and 4000 Hz. This is the range most critical for understanding speech. A threshold of 15 dB at 250 Hz and 20 dB at 8000 Hz, with everything in between at 10 dB, is a perfectly normal result. The slight variation between frequencies reflects natural, minor differences in sensitivity that everyone has.
If your audiogram shows any points dipping below 20 dB at one or more frequencies, that frequency-specific hearing loss may or may not affect your daily life depending on where the dip occurs and how deep it goes. A threshold of 25 dB at a single frequency is considered minimal and may not be noticeable. Thresholds of 35 dB or worse begin to affect your ability to follow conversations, particularly in background noise.