To work out what cycle phase you're in, you only need two numbers: how many days it's been since your last period started, and how long your cycles usually run. Days 1–5 are typically the menstrual phase, ovulation lands roughly 14 days before your next period, the follicular phase fills the stretch before it, and the luteal phase covers everything after — right up to day one of the next bleed.
That's the whole trick, and the calculator below does the counting for you. If you got here hunting for a "which phase of my cycle am I in" quiz — good news, you can skip the twelve questions about whether you cried at a dog video. Your phase comes from dates, not vibes. The crying is just corroborating evidence.
Under the calculator you'll find what each phase typically feels like — energy, mood, social battery — described the way weather deserves to be described: honestly.
What cycle phase am I in today? The instant phase finder
Enter the first day of your most recent period and your average cycle length — that's day one of one period to day one of the next. 28 is the textbook default; your body did not read the textbook, so use your real number if you know it.
One caveat, delivered with love: this is date math built on typical cycle patterns. Ovulation is not contractually obligated to arrive exactly 14 days before your period — it drifts, especially if your cycles are irregular. Treat the result as a forecast, not a subpoena.
The four cycle phases, and how they typically feel
A cycle is a loop of four phases, and each one has its own weather system. Here's the typical pattern — yours may run warmer or colder.
Menstrual phase (about days 1–5): low-battery mode
Day one is the first day of full bleeding, and hormones are at their lowest ebb. Typical forecast: energy in the basement, social battery flickering, and a strong gravitational pull toward horizontal surfaces. Cramps, fatigue and headaches like to make cameos. Rest isn't laziness this week — it's the schedule.
Follicular phase (after your period, until the ovulation window): the climb
Estrogen starts climbing and takes you with it. This is the stretch where plans sound doable, ideas sound genius, and a workout feels suspiciously pleasant. Typical readings: energy and mood trending up day by day, skin cooperating, social battery recharging fast. If you've been putting off something hard, start it here.
Ovulation (roughly a 3-day window): peak broadcast
Ovulation usually lands about 14 days before your next period — around day 14 of a 28-day cycle — with a fertile-feeling window of about three days around it. Typical forecast: peak energy, peak charm, peak libido, and a mysterious urge to text first. Enjoy the high. It's brief, and the group chat will hear about it.
Luteal phase (after ovulation, until your next period): the volume goes up
Progesterone takes over, and for many people the final week gets loud — this is the home of the famous luteal phase mood swings. Typical readings: energy dipping, tolerance dipping faster, cravings filing formal requests, skin staging a small protest. What you feel is real; late luteal just turns the amplifier up. One honest signpost while we're talking symptoms: if cramps, mood dips or anything else in any phase regularly feel severe or derail your life, that's a conversation for a clinician, not a calculator.
How to do it with Hormoscope
The calculator above is a snapshot. Hormoscope: Hormone Forecast runs the same math live, every day, and turns it into something you can plan around — a weather app, but for your hormones.
- Download Hormoscope — free, no account, no sign-up. Your cycle data never leaves your phone, and intimacy logs sit behind Face ID.
- Log your last period start date. The free-forever calendar immediately shows your cycle day, phase-colored days, and your predicted next period.
- Check your phase at a glance. The calendar tracks where you are live, so "what cycle phase am I in" stops being a finger-counting exercise.
- Open Today for the daily reading (Hormoscope Pro) — one sharp line about how the day will feel, tuned to your exact phase. Bloom day or Storm day, you'll know before you're out of bed.
- Watch the five meters — Energy, Mood, Social Battery, Skin and Libido, each scored 0–100 and tuned to your phase, so "the climb" and "the volume goes up" become actual numbers.
- Plan with The Briefing — your week of hormone weather with per-day scores. Put the big meeting in your follicular climb and the couch in your late luteal.
- Log symptoms in seconds — cramps, headache, bloating, fatigue, acne, cravings, plus flow intensity — and discover your cycle archetype: your hormone type and what it says about you.
What does a phase-tuned reading sound like? Here's a real one, from Day 26, deep luteal:
"Your standards are at an all-time high and your tolerance at an all-time low. Avoid the comments section."
The calculator tells you where you are. The forecast tells you what to do about it.
Cycle phase FAQ
How do I figure out what cycle phase I'm in without an app?
Count the days since your last period started. Days 1–5 are typically menstrual; ovulation usually sits about 14 days before your next period, with a window of a few days around it. Between period and window is follicular; after the window is luteal.
Is there a "which phase of my cycle am I in" quiz?
Symptom quizzes exist, but your phase comes from dates, not multiple choice. A cycle phase calculator using your last period date and average cycle length gives a more reliable answer — symptoms make good corroborating evidence, not good math.
Why are luteal phase mood swings so intense?
After ovulation, estrogen dips and progesterone rises, and for many people that combination turns the emotional volume up — irritability, cravings and mood dips are a typical late-luteal pattern. As Hormoscope puts it: what you feel is real, it's just amplified right now. If it regularly derails your life, raise it with a clinician.
How accurate is a cycle phase calculator?
For regular cycles, it's a solid estimate. But ovulation timing drifts from person to person and month to month, so treat the answer as a forecast, not a lab result. A tracker that recalculates from the periods you actually log — the way Hormoscope's calendar does — gets sharper with every cycle.
