Fertile-window context

Ovulation calculator for partner planning

See a rough fertile-window estimate next to the period window, with confidence clearly marked.

Estimate the window
Fertile window beside period windowConfidence labelsOne signal is enough to start
Start with one signal
What did she mention?
When?

Selected Jul 10

How it works

Estimate from one period signal

Useful for planning context only. Do not use this as contraception or medical advice.

  1. Enter the period signal
  2. Review the fertile window
  3. Refine after more starts

Product proof

A real dashboard, not a 28-day guess.

Roostercal turns one sparse signal into a row you can act on: next window, fertile window, confidence, quick logging, reminders, and calendar export.

Open the dashboard
ChickNowNext periodMove
BealutealJul 14-18Reduce friction
Quick logBleedingStartedLateNote
Reminder plan2-day heads-up, expected start, late check-in
Export .ics

Use cases

Built for the real sparse-data workflow

  • Plan romantic weekends
  • Understand cycle timing better
  • Avoid over-reading weak data

Pricing

One row free. More with Pro.

Free saves one active row and includes data export. Pro is $7/mo or $49/yr for additional rows, automatic check-ins, a live calendar, weekly planning, and forecast history.

Start free

FAQ

Practical answers

Can this predict ovulation exactly?

No. It estimates a window. Exact ovulation requires stronger evidence than sparse partner logs.

Can this prevent pregnancy?

No. It must not be used as contraception.