At what age do periods start?

Bottom lineMost first periods (menarche) happen between ages 10 and 15, averaging about 12, and are often irregular for the first 1 to 2 years as the cycle settles; see a doctor if there's no period by age 15 (or no puberty signs by 13), no period within 3 years of breast development, periods that stop after being regular, or very heavy, painful, or disruptive periods.

Most people get their first period (called menarche) between ages 10 and 15, with the average around 12. There's a wide normal range, and timing is influenced by genetics, weight, and overall health.

What to expect

• First periods are often irregular for the first 1 to 2 years while the cycle settles
• Cycles may be longer, shorter, or skipped at first
• Flow and length can vary a lot early on

This is normal as the hormonal system matures.

Signs a period may be coming soon

• Breast development (usually starts about 2 years before)
• Vaginal discharge appearing in the months before
• A growth spurt

When to check with a doctor

• No period by age 15, or no signs of puberty by 13
• No period within 3 years of breast development
• Periods that were regular then stop
• Very heavy, very painful, or extremely irregular periods that disrupt life

Early tracking helps a teen learn their pattern as cycles settle.

Map cycles with the Menstrual Cycle Calculator and read about the four cycle phases.

Femora helps track those first irregular cycles so a normal pattern becomes clear over time.