⚠️ Reference only — not a diagnosis
This tool provides general health information and is not a medical diagnosis. If you suspect menstrual problems or perimenopause symptoms, see an OB-GYN.
Menstrual Irregularity & Perimenopause Signal Checker
Enter your recent period start dates to get an irregularity grade from average cycle length and CV%, plus a perimenopause signal check if you are 40 or older.
📅 Enter period start dates
Enter your period start dates for the last 6 months (3 minimum). Empty fields are ignored.
Perimenopause signals are checked for ages 40 and older.
🔒 Your period start dates and age are never sent to a server. All math runs in your browser; records are stored only in this browser (localStorage) and in share links you create.
📊 Analysis
Enter at least 3 period start dates to see average cycle length, CV%, and an irregularity grade. (0 entered so far)
Data sources · verification
- 🏥 Normal cycle 21–35 days, avg 28: Korean Society of OB-GYN / ACOG
- 📐 Perimenopause staging: STRAW+10 (Stages of Reproductive Aging Workshop)
- 📚 Menstruation & menopause info: Seoul National University Hospital
Verified: 2026-06-20
※ CV thresholds (10%, 20%) and signal criteria are reference values to aid interpretation and may differ from clinical diagnostic standards.
Guide · FAQ · bal.pe.kr 도구 모음
계산 방법·기준은 Guide, 자주 묻는 질문은 FAQ, 데이터 출처·운영 정보는 About 참조. Last updated 2026-06-20.