How do you calculate percentage of hearing loss from an audiogram?

A percentage figure can be a helpful way to summarise hearing loss, but it is not read straight off the graph. An audiogram plots the quietest sounds you can hear at different pitches, and turning those points into a percentage requires a recognised calculation. Several formulas exist, which is why the same audiogram can produce slightly different percentages depending on the method used.

What does an audiogram actually show?

An audiogram maps your hearing thresholds in decibels (dB) across a range of frequencies, usually from 250 Hz (low pitch) to 8000 Hz (high pitch), for each ear. The lower the marks sit on the chart, the louder a sound must be before you detect it. On its own the chart shows the pattern and degree of loss, not a single percentage.

How is a percentage worked out?

Most methods follow the same broad steps:

• Select the key frequencies that carry speech, often 500, 1000, 2000 and 3000 Hz.
• Average your thresholds at those frequencies to get a figure in decibels.
• Subtract a "low fence" — a level below which hearing is treated as effectively normal.
• Multiply the remaining decibels by a set factor to convert to a percentage for that ear.
• Combine the two ears, usually weighting the better ear more heavily, to reach a binaural percentage.

Different systems use different frequencies, fences and weightings, so the resulting number depends on which recognised formula applies to your situation.

Why is the better ear weighted more?

When the two ears are combined into a single binaural figure, many formulas give the better ear more weight, sometimes counting it several times as heavily as the poorer ear. The reasoning is that everyday listening leans heavily on your stronger ear, so it reflects your practical hearing more closely. This is one reason a percentage can look lower than you might expect when one ear hears much better than the other, and it is another example of why the calculation is best left to a professional.

Why are there different methods?

Percentage figures are often needed for specific purposes, such as workers' compensation or certain support assessments, and each scheme may specify its own approved method. In Queensland, for instance, WorkCover claims for noise-induced hearing loss follow a defined process. Because the "right" formula depends on why the percentage is needed, this is something an audiologist calculates using the correct method for your circumstances rather than a figure you estimate yourself.

What does the percentage really mean?

It is worth remembering that a percentage is a summary, not a complete description of how you hear. Two people with the same percentage can cope quite differently depending on speech clarity, background noise and tinnitus. The number is useful for comparisons and eligibility, but your day-to-day experience is shaped by more than that single figure. If you need a documented percentage — for a compensation claim, an employer, or a support application — an audiologist can perform the assessment and apply the appropriate formula. At Hearing Help in Newport Marketplace on the Redcliffe Peninsula, our audiologists can test your hearing, explain your audiogram in plain language, and where relevant calculate a percentage using the method your situation requires. No referral is needed to book a hearing assessment, and having accurate, professionally interpreted results means any figure you rely on is calculated correctly.