WHO Grades of Hearing Impairment Interpreter
WHO Grades of Hearing Impairment Interpreter
Place a better-ear four-frequency pure tone average in WHO’s 2021 grades of hearing loss or in the earlier WHO grades, and see where the two disagree — because both are still in use and the same audiogram can fall in differently-named grades.
WHO grade of hearing loss
2021 grades and the previous onesBetter ear 38 dB HL, worse ear 55 dB HL, both as the average of 500, 1000, 2000 and 4000 Hz; WHO 2021 grades selected
The two versions side by side, on the better-ear four-frequency average
| Better-ear PTA (dB) | WHO 2021 grade | Previous WHO grade |
|---|---|---|
| under 20 | Normal hearing | Grade 0, no impairment |
| 20 up to 25 | Mild hearing loss | Grade 0, no impairment |
| over 25 up to under 35 | Mild hearing loss | Grade 1, slight impairment |
| 35 up to 40 | Moderate hearing loss | Grade 1, slight impairment |
| over 40 up to under 50 | Moderate hearing loss | Grade 2, moderate impairment |
| 50 up to 60 | Moderately severe hearing loss | Grade 2, moderate impairment |
| over 60 up to under 65 | Moderately severe hearing loss | Grade 3, severe impairment |
| 65 up to 80 | Severe hearing loss | Grade 3, severe impairment |
| over 80 up to under 95 | Profound hearing loss | Grade 4, profound impairment |
| 95 or more | Complete or total hearing loss | Grade 4, profound impairment |
| Better ear under 20 with worse ear 35 or more | Unilateral hearing loss | No category — grades as grade 0 |
What the 2021 revision changed
| Element | Previous WHO grades | WHO 2021 |
|---|---|---|
| Upper limit of normal hearing | 25 dB | 20 dB |
| Grades above normal | Four (grades 1 to 4) | Six (mild to complete or total) |
| Step between boundaries | 15 dB, then 20, then 20 | A consistent 15 dB step |
| Unilateral hearing loss | No category; excluded from disabling hearing impairment at any severity | A category of its own |
| Disabling hearing loss | Grades 2 to 4: more than 40 dB in adults, more than 30 dB in children | More than 35 dB in the better hearing ear |
| Frequencies averaged, and which ear | 500, 1000, 2000 and 4000 Hz in the better ear | 500, 1000, 2000 and 4000 Hz in the better ear — unchanged |
Two WHO schemes, both in use, and how this page sources them
WHO’s grades of hearing loss do one narrow job: they divide the better ear’s four-frequency pure tone average into named strata. Two things about that sentence are specified and are routinely got wrong. The average is taken over 500, 1000, 2000 and 4000 Hz — not the three-frequency speech average, and not the 500/1000/2000/3000 Hz set used for impairment percentages — and it is taken in the better hearing ear. Grading the worse ear overstates the grade; using a three-frequency average understates a high-frequency loss, often by a whole grade.
The 2021 World report on hearing replaced the grades that had been in use since the 1990s. The limit of normal hearing came down from 25 to 20 dB, four grades above normal became six on a consistent 15 dB step, the labels changed, a top category of complete or total hearing loss was separated from profound, and unilateral hearing loss was given a category of its own — the earlier scheme graded only the better ear and explicitly excluded unilateral loss of any severity from disabling hearing impairment, so a person deaf in one ear graded as having no impairment. Both schemes are still in circulation, in papers, in registries and in local protocols, and a report often does not say which it used.
Separately from the grades, WHO defines disabling hearing loss, and that definition also moved: it is now hearing loss greater than 35 dB in the better hearing ear, where the earlier scheme’s disabling threshold was more than 40 dB in adults and more than 30 dB in children. A prevalence figure therefore cannot be compared across the change without saying which definition produced it.
How this page is sourced matters enough to state on it. The grade table in the World report on hearing is a figure rather than text and could not be read: the report’s own 8 MB PDF would not open, the executive summary contains no table, and two journal reproductions of it returned the caption alone. The boundaries used here are therefore taken from two independent readable sources that agree on every value either of them states, with the 95 dB boundary supplied by the second, and the label set is taken from a WHO training manual. The published account of the revision independently predicts the same ladder by stating that the six bilateral categories were separated by a consistent 15 dB step from a 20 dB floor. The unilateral row is a reconstruction and is labelled as one on the result. Audiometric results are equipment- and calibration-dependent: the dB HL scale is defined against the reference equivalent threshold levels of the ISO 389 series for a particular transducer and coupler, so the same ear can read differently on two audiometers, and the BSA recommended procedure puts the uncertainty of any threshold measurement at no better than plus or minus 5 dB. Your own audiogram and the calibration standard it was recorded against govern, not this arithmetic.
Frequently asked questions
What are the WHO 2021 grades of hearing loss?
Seven bilateral strata on the better ear’s average at 500, 1000, 2000 and 4000 Hz: normal hearing under 20 dB, mild 20 to under 35, moderate 35 to under 50, moderately severe 50 to under 65, severe 65 to under 80, profound 80 to under 95, and complete or total hearing loss at 95 dB or more. Unilateral hearing loss is a separate category.
How do the 2021 grades differ from the older WHO grades?
The limit of normal hearing fell from 25 dB to 20 dB, four grades above normal became six on a consistent 15 dB step, the labels changed, complete or total hearing loss was split off from profound, and unilateral hearing loss gained a category it had not had. The frequency set and the use of the better ear did not change.
Can the same audiogram get different WHO grades?
Yes, and over wide stretches of the scale rather than only at the edges. A better-ear average of 38 dB is a moderate hearing loss under the 2021 grades and grade 1, slight impairment, under the previous ones. An average of 22 dB is a mild hearing loss under the 2021 grades and no impairment at all under the earlier scheme.
Which ear and which frequencies does a WHO grade use?
The better hearing ear, and the average of the air-conduction thresholds at 500, 1000, 2000 and 4000 Hz. Both are specified and both are often wrong in practice — a three-frequency average will understate a high-frequency loss, and grading the poorer ear will overstate the grade.
What is disabling hearing loss, and is it a grade?
It is not a grade. It is a separate threshold WHO uses for prevalence estimates, now set at hearing loss greater than 35 dB in the better hearing ear. The earlier definition was grades 2 to 4, which meant more than 40 dB in adults and more than 30 dB in children, so figures either side of the change are not comparable.
Related calculators
References
- World Health Organization. World report on hearing. Geneva: WHO, 2021. (Grade table not readable as text; see this page’s note on how the grades are sourced.)
- World Health Organization. Deafness and hearing loss. WHO fact sheet. Geneva: WHO.
- Olusanya BO, Davis AC, Hoffman HJ. Hearing loss grades and the International classification of functioning, disability and health. Bull World Health Organ. 2019;97(10):725–8.
- Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR). Potential health risks of exposure to noise from personal music players and mobile phones. Brussels: European Commission, 2008. Section 3.4.1, Table 4 (reproducing the earlier WHO grades of hearing impairment).
- Keidser G, Naylor G. A need for a universal approach to characterize hearing loss and its consequences. Front Aging Neurosci. 2022;13:769405.
- World Health Organization. Primary ear and hearing care training manual. Geneva: WHO.
Not medical advice. For healthcare professionals and education. Reference intervals vary by laboratory and assay — always use your own laboratory's. Never base a dose or a treatment decision on this page alone. Full disclaimer at calcengines.com/disclaimer/