Number of illiterates


The number of persons that cannot read and write. Illiteracy is typically measured according to the inability to comprehend a short simple statement on everyday life. The adult illiterate population corresponds to ages 15 and above, the youth to ages 15 to 24, and the elderly to ages 65 and above. Generally, literacy also encompasses numeracy, and measurement may incorporate a simple assessment of arithmetic ability. Illiteracy should be distinguished from the failure to meet minimum proficiency levels of functional literacy. The latter is a more comprehensive measure assessed on a continuum in which multiple proficiency levels can be determined.

Data source

Population census, household surveys, labour force surveys.

Source definition

UNESCO Institute for Statistics

Calculation method

Use data on the number of illiterates or multiply the respective population by one minus the literacy rate.

Data required

Number of illiterates by age-group, or the population by age-group and the corresponding literacy rate.


The higher the illiterates population of the country, the greater the need to expand primary education and adult literacy programmes. When disaggregated by geographical locations, this indicator can pinpoint the areas needing most literacy efforts, and policies may be set to target such efforts at priority population groups of a particular gender and age group(s).


Some countries apply definitions and criteria for literacy which are different from the international standards, or equate persons with no schooling to illiterates, or change definitions between censuses. Some assessments of literacy may also rely on self-reporting, possibly reducing accuracy. In countries where nearly all individuals have completed basic education, the literacy rate provides limited information on the variance of literacy skills in the population.


To identify the size and characteristics of the illiterate population, informing policies expanding education and literacy programmes.

Quality standards

To increase comparability, measures of adult literacy should align with the standard international definition. If possible, an assessment of functional literacy is preferred for comprehensiveness and relevancy.

The UIS maintains a global database on literacy data as well as literacy definitions used by countries during data collection.

Types of disaggregation

By sex and the following age groups: 15 and above, 15 to 24, 25 to 64, 65 and above.