What phase of my cycle am I in? Free phase finder
Cycle day 11
You’re in your fertile window
Typical mood: Bright, social, confident. Peak energy. This is your most fertile time.
🔒 Calculated in your browser. Nothing you type is sent or stored. Estimates only: cycles vary.
Count from the first day of your last period: that's cycle day 1. Your period is the menstrual phase, then comes the follicular phase, the fertile window around ovulation (about 14 days before your next period), and the luteal phase until your next period. Enter your dates above and the finder shows your cycle day and phase today.
How the phase finder works
You give it three things: the first day of your last period, your usual cycle length and how long you bleed. It rolls forward to the cycle you're in today, works out your cycle day, and places today in one of four phases. You'll also see a mini calendar of the whole cycle colored by phase, with a sun on the estimated ovulation day.
- Period (menstrual phase): from day 1 until your bleeding usually ends.
- Follicular phase: from the end of your period until the fertile window opens.
- Fertile window (ovulatory phase): the five days before estimated ovulation, ovulation day and the day after.
- Luteal phase: from the end of the fertile window until the day before your next period.
The phases are worked out from averages, so the edges are fuzzy, especially if your cycles vary. Everything stays in your browser.
What each phase usually feels like
Phases aren't just about bleeding and fertility. Hormones shift across the cycle, and many people notice a matching rhythm in mood, energy, sleep and appetite. Everyone is different, but these are the patterns people most often describe.
How long is each phase?
| Phase | Typical length | What varies |
|---|---|---|
| Menstrual | 2 to 7 days | Bleeding length, from cycle to cycle and person to person |
| Follicular (including the period) | about 10 to 22 days | This is the part that stretches or shrinks and changes your cycle length |
| Ovulation | about 1 day (egg lives 12 to 24 hours) | The day itself can shift with stress, illness or travel |
| Luteal | about 11 to 17 days, often 12 to 14 | Fairly steady for each person |
Because the follicular phase is the flexible one, a late ovulation pushes your luteal phase and your next period later too. If the finder says you're in the luteal phase but you feel like you're mid-cycle, your ovulation may simply be late this month. For a deeper look at each stage, see the four phases of the menstrual cycle.
Why knowing your phase helps
- Plan around your energy: put demanding work, workouts or social plans in the follicular and ovulatory days if they tend to feel easier.
- See PMS coming: if the late luteal phase tends to feel heavy, you can lighten your calendar and be gentler with yourself. Read luteal phase mood.
- Make sense of symptoms: spotting, discharge, breast tenderness and cravings often make more sense once you know your cycle day.
- Talk to a doctor with facts: cycle day and phase are what clinicians ask about first.
Lulu shows your phase every day and learns from one-tap mood check-ins how you usually feel in each one, so you get a gentle heads-up before your harder days.
When to talk to a doctor
See a doctor if your cycles are often shorter than 21 days or longer than 35, if you bleed between periods or after sex, if your periods stop for 3 months or more, or if low mood before your period is affecting your life.
Frequently asked questions
What are the 4 phases of the menstrual cycle?
Menstrual (your period), follicular, ovulatory and luteal. The follicular phase technically starts on day 1 and overlaps with your period.
What cycle day am I on?
Count the first day of your last period as day 1 and count forward to today. The finder above does it for you. See also what day of my cycle am I on.
Which phase has the most PMS?
The late luteal phase, usually the last 5 to 10 days before your period, when estrogen and progesterone fall.
Can I be in a different phase than the calculator says?
Yes. If you ovulate early or late, every phase after that moves. LH tests or temperature tracking can show where you really are.
Sources
- Cleveland Clinic: Menstrual cycle
- Cleveland Clinic: Luteal phase
- Office on Women's Health: Your menstrual cycle
This page is for information only and isn’t medical advice. If something worries you, please talk to a doctor.
Keep reading
Period mood calculator: how might I feel today?Period mood calculator: find your cycle phase today and the mood people often feel in it, then learn how to build a personal forecast from your own days.The 4 phases of the menstrual cycle, in colorThe 4 phases of the menstrual cycle explained simply: what your hormones do in each, how long each lasts, and how mood and energy usually change.Menstrual cycle mood: how you feel in each phase, and whyHow menstrual cycle mood changes through all four phases: what hormones do, why some people feel it more, and how to learn your own pattern.
What day of my cycle am I on? How to count itWhat day of my cycle am I on? Count from the first day of real bleeding as day 1. A simple method, a worked example, and what each cycle day usually means.
Ovulation calculator: when do I ovulate?Free ovulation calculator: enter your last period and cycle length to see your likely ovulation day for the next 4 cycles. Private, instant, estimates only.