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About this tool
Informational Tanner stage timeline showing typical age ranges for each pubertal change in girls and boys, with early and delayed flags.
The Puberty Stage Timeline Guide lays out the typical age window for every Tanner stage and pubertal milestone, then checks whether a child's first sign appeared inside that window. It uses the Tanner sexual maturity rating scale described by Marshall and Tanner, together with the conventional clinical thresholds of before 8 years in girls and before 9 years in boys for early puberty, and no first sign by 13 in girls or 14 in boys for delayed puberty. It is written for parents and older teenagers who want a reference point rather than a diagnosis.
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Each of the five stages is described by what is actually visible, alongside the age band it usually spans.
The early and delayed cut-offs shown are the conventional ones clinicians use, not vague guesses.
Shows that testicular enlargement, not pubic hair or voice change, is the true first sign in boys.
In girls the first sign, breast budding, usually appears between 8 and 13 years with a median near 10.5. In boys the first sign is testicular enlargement to about 4 mL, usually between 9 and 14 years with a median near 11.5. Pubic hair can appear separately and is not a reliable marker of puberty starting.
Conventionally, pubertal signs before age 8 in girls or before age 9 in boys are described as precocious and are worth a paediatric assessment. Early breast tissue alone in a toddler is often isolated premature thelarche rather than true puberty, which is one reason a clinician should make the call rather than a chart.
If a girl has no breast development by 13, or no period by 15, and if a boy has no testicular enlargement by 14, that is the usual point at which doctors investigate. Most such children have constitutional delay of growth and puberty, a normal variant that resolves on its own, but the evaluation is still worth doing.
Menarche typically follows breast budding by about 2 to 2.5 years, and almost always within 3 years. The median age at first period is around 12.5 years, and girls usually grow a further 5 to 7.5 cm after it. A gap longer than 3 years, or no period by 15, should be discussed with a doctor.