CycleBook: Period Tracker App

CycleBook is a private period tracker and menstrual cycle calendar that works fully offline. Log your period, symptoms and mood, see your next periods and an estimated fertile window, and keep every detail on your own phone.

One-time purchase · No subscription · No ads · No account · Works offline · No internet permission

Period tracker and calendar
• One tap logs a period start or end, with flow from spotting to heavy
• Month calendar with period and predicted days, the estimated fertile window and ovulation day
• Next 3 periods, each with a likely day, a range and a confidence label
• Period reminders, a late-period alert, and wider ranges when your cycles vary

Ovulation and fertile window (estimates)
• Ovulation (LH) and pregnancy tests, and cervical mucus
• Basal body temperature (BBT) chart in °C or °F, with temperature shift and coverline

Symptoms, mood and notes
• Cramps, headache, bloating, acne, fatigue and more, with intensity and your own symptoms
• Mood, energy, a 1–6 day rating and notes with search
• Symptom heatmap by cycle day

Pill reminders and pregnancy mode
• Daily pill reminder for 21/7, 24/4, 28-day or continuous packs, with Taken and Snooze
• Pill history: taken, late, skipped or not marked, day by day
• Pregnancy mode with week, trimester and estimated due date; period predictions pause

Explain your cycle
• Mark an unusual cycle (illness, stress, travel, a birth-control change) or leave it out
• "Why this range?" explains each prediction; estimates can follow your last 3, 6 or 12 cycles
• Patterns: symptoms that often return in the same part of your cycle (info only)
• Ring, patch, injection, implant or IUD check date, each with a countdown
• Your own tags (coffee, workout, travel) and a weight log in kg or lb

Look back at your cycles
• Last-cycle recap, compare cycles row by row, find every day you logged a symptom or mood
• Before and after your period: the week before each period next to days 4–10, also on the report
• Edit a period's first day and length in one place; spotting outside periods is shown
• Own reminders for anything; a date calculator for periods, ovulation and due date (est.)

Every stage of life
• Profiles with their own PIN, for a teen or a shared phone
• Perimenopause view: 2-year cycle trend, hot flashes, sleep. Postpartum mode with breastfeeding
• Simple mode: big buttons, next 7 days as pictures, read aloud

Plan, share and learn
• Log pads, tampons, cups, clots, leaks and pain (0–10), with a change reminder and a supplies count
• "Will my period overlap?" for a trip or event (est.); type past periods in one list
• Share an encrypted, dates-only file with a partner, and read 24 short offline explainers

Charts and doctor report
• Average cycle and period length, variability and cycle charts, each also as a table
• Doctor report (last 6 or 12 cycles, symptoms, products, pain, ratings) as a PDF to share or print; CSV on Android 4.3
• Questions for your visit printed on the report, a month summary under the calendar and a cycles table (CSV)

Private by design
• No internet permission: your cycle data stays on your phone, with no cloud and no sign-up
• PIN or fingerprint lock; discreet mode with a neutral icon, name and notification text
• Details can delete themselves after 6, 12 or 24 months
• Encrypted backup to a file you keep, easy move to a new phone
• Import other trackers' exports or CSV; export to CSV and JSON anytime

Made for older phones
Runs on Android 4.3 and newer, under 2 MB, fast with 1 GB of RAM.

Tablet, widgets and Wear OS
• Two-pane tablet layouts, a year view, home-screen widgets, shortcuts and dark mode
• Wear OS app with a today card, quick log, a tile and complications

Available in 20 languages, including English.

CycleBook is a tracking and estimation tool, not a medical device. It must not be used as contraception or to diagnose any condition. Talk to a healthcare professional about your health.

Questions or ideas? Write to [email protected].