Key Stage

A Key Stage is a stage of the state education system in the United Kingdom and Gibraltar setting the educational knowledge expected of students at various ages.

The stages are as follows:
 * Key Stage 0: Nursery and reception years (3-5 years old). Now included as part of the Early Years Foundation Stage
 * Key Stage 1: Years 1 to 2 (5-7 years old)
 * Key Stage 2: Years 3 to 6 (7-11 years old)
 * Key Stage 3: Years 7 to 9 (11-14 years old)
 * Key Stage 4: Years 10 to 11 (14-16 years old). The exams at the end are typically of the GCSE level.
 * Key Stage 5 (more commonly referred to as "Sixth Form"): Years 12 to 13 (16-18 years old). The exams at the end are typically A-Levels, AS-Levels, NVQs or HNDs.

The National Curriculum sets out targets to be achieved in various subject areas at each of the Key Stages.

The Key Stages were first defined in 1988 Education Reform Act to accompany the first introduction of the National Curriculum. The precise definition of each of the main 4 Key Stages is age-related, incorporating all pupils of a particular age at the beginning of each academic year. The Key Stages were designed to fit with the most prevalent structures which had already grown up in the education system over the previous 100 years of development.

Key Stage 1 fits broadly with the first stage of primary education, often known as infant schools. This break had existed for some time, being acknowledged in the 1931 Hadow report as 'axiomatic' by as early as 1870.

Key Stage 2 fits the later stage of primary education, often known as junior schools. Again, described by Sir William Henry Hadow, this took pupils up to the standardised break at age 11.

Secondary education was split between Key Stages 3 and 4 at age 14, to align with long-existing two-year examination courses at GCSE level.

Key Stages 0 and 5 have no legal definition, and are merely used as indicators to complement the defined Key Stages.