Calendar phases and “estimated”
What Follicular · estimated means, and how that differs from the next-period forecast.
On the Calendar home card, Ciclo may show something like Cycle day 7 and Follicular · estimated. The phase name is the claim. The word estimated (Spanish UI: estimada) is a confidence label, not a second phase.
This page is about what the app is doing. For general biology of the cycle, use the Learn tab.
What “estimated” means
Estimated means: this phase is inferred from calendar timing and your logged period history. It is not confirmed by a measurement that day.
| Source | When it appears | Meaning |
|---|---|---|
| Observed | Flow is logged on that day | Phase is Menstrual, from the diary |
| Estimated | No flow that day, forecasting is on, and Ciclo can place the day inside a cycle | Phase is a timing guess |
Follicular · estimated does not mean “we scored how follicular you are.” It means: “we think you are in the follicular part of the cycle, and that guess is estimated.”
The four labels
| Phase | Inner season (if enabled) | Rough idea in the UI |
|---|---|---|
| Menstrual | Winter | Bleeding / early cycle |
| Follicular | Spring | After bleeding, before the estimated ovulation window |
| Ovulation | Summer | Timing window before the next expected period start |
| Luteal | Fall | After that window, until the next period |
These labels are educational context. They are not a diagnosis, a fertility test, or contraception.
How Ciclo picks a phase
- Find the cycle that contains today: last period start on or before today, and the next start (logged, or the forecast most-likely date).
- If today’s diary has flow → Menstrual, source observed.
- Otherwise, if estimated phases are allowed:
- Days from cycle start through the expected bleeding length → Menstrual, still estimated if you did not log flow.
- A window about 16–10 days before the next period start → Ovulation, estimated.
- Before that window → Follicular, estimated.
- After that window → Luteal, estimated.
If you turn forecasting off, Ciclo only shows a phase when flow is observed.
When the expected day passes
The most likely start is taken from the full forecast, before days already passed are dropped. The calendar keeps that day marked. It does not move the marker forward.
If that day arrives and you have not logged a new period start, the home card stays on the phase (usually Luteal · estimated). On that day it says the period may start today. After it, the card counts days late from that date. It also quotes today's chance from the initial forecast. Example: if 10 October was 30%, 11 October 15%, and 12 October 11%, then on 12 October the card says you are 2 days late and that the initial forecast gave today an 11% chance. It does not rebuild the chart so today looks like the new most likely day.
The Patterns tab still shows the forecast with past days removed. That chart answers “what is still ahead?” The calendar does not.
Not the same as the period forecast
The forecast engine predicts the next period start. Phase labels reuse those dates as a calendar story. They are not a clinical ovulation model.
OpenCiclo does not claim to confirm ovulation. Do not use Ciclo as birth control.
When it can look wrong
- Cycles vary a lot in length.
- Starts or flow were logged late or incompletely.
- There is little history, so the next start leans on a population typical length.
- Real ovulation is not sitting in that fixed pre-period window.
That is why estimated stays on the card.