Puberty Stage Timeline Guide
Informational Tanner stage timeline showing typical age ranges for each pubertal change in girls and boys, with early and delayed flags.
About this tool
Puberty Stage Timeline Guide
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.
How to use Puberty Stage Timeline Guide
- 1
Open Puberty Stage Timeline Guide on AltFTool — it loads instantly in your browser.
- 2
Set Reference chart to Girl or Boy and enter Current age (years).
- 3
Enter Age at first sign (years, blank if none yet) — breast budding for girls, testicular enlargement to 4 mL for boys — plus Age at first period (optional) on the girls' chart.
- 4
Read Timing of the first pubertal sign against the early and delayed cut-offs, check the Milestone windows table of typical ages, then press Copy result.
Why use Puberty Stage Timeline Guide
Tanner stages in plain words
Each of the five stages is described by what is actually visible, alongside the age band it usually spans.
Named clinical thresholds
The early and delayed cut-offs shown are the conventional ones clinicians use, not vague guesses.
Milestone ordering, not just ages
Shows that testicular enlargement, not pubic hair or voice change, is the true first sign in boys.
Common use cases
- A parent notices breast budding in a nine-year-old and wants to know where that sits in the normal range before booking an appointment.
- A 14-year-old boy has not started puberty and his family wants to know the age at which doctors normally investigate.
- A girl started breast development at 10 and the family wants a realistic window for when her first period is likely to arrive.
- A school nurse or coach wants a plain reference for when the growth spurt typically peaks in each sex when planning training loads.
Frequently asked questions
At what age does puberty normally start?
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.
What counts as early or precocious puberty?
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.
When is puberty considered delayed?
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.
How long after breast development does the first period come?
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.