Menstrual cycle phase calculator
Estimate your current cycle phase from your period dates.
Track the pattern, not just one result
This free tool gives you an educational starting point. Use Flow & Glow to keep period dates, symptoms, and cycle notes together so changes are easier to discuss with a qualified healthcare professional.
How to read your result
The menstrual cycle is commonly described in four phases: menstrual, follicular, ovulatory, and luteal. Estrogen and progesterone change across these phases, but timing and symptoms vary from person to person and from cycle to cycle.
This calculator uses your last period date and usual cycle length to estimate where you may be today. It cannot confirm ovulation or hormone levels, so use the result as a calendar-based guide rather than a diagnosis.
What phase estimates can tell you
A phase estimate can help you compare recurring symptoms with cycle timing. It should not be used to prescribe workouts, food, or productivity around a predicted phase because responses differ and the evidence for universal cycle-syncing rules is limited.
For a clearer personal pattern, track period dates and the symptoms that matter to you across several cycles. Seek clinical advice for severe, sudden, persistent, or disruptive changes.
Related clinician-reviewed guides
Try another free cycle tool
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- Implantation calculator — Estimate your implantation window and the best day to test.
- Ovulation calculator — Know when your body is most likely to conceive.
Frequently asked questions
What if I don't know my last period's start date?
You can enter your best estimate, but the result will be less reliable. Update the date when you know it, and compare estimates with your actual period dates over several cycles.
Are these ranges the same for everyone?
No. They are calendar-based estimates. Phase timing varies between people and cycles, and a date estimate cannot confirm ovulation. Use it as a guide alongside your actual period dates and symptoms.
Trust and medical boundaries
This tool is educational and doesn't replace medical advice. If something feels off, talk to a qualified clinician.
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