BBT Chart - Simple Fertility

Record basal body temperature and view it in a clear graph, keeping day-to-day fertility tracking easy to review.

BBT Chart is a simple, lightweight fertility log dedicated to one thing: a digital version of the paper basal body temperature sheet, plus automatic interpretation.

■ One-second morning log The entry screen opens instantly, with the picker preset to your last value - nudge it and tap Save. Includes ±0.01 fine-tune buttons, period-start marks, one-line notes, and a daily 7:00 reminder (changeable).

■ A biphasic chart you can trust Line charts are generated per cycle. The thermal shift is detected by a clear, documented rule (3-over-6: three consecutive days above the highest of your previous six readings), and the coverline uses that same maximum. The rule is spelled out inside the app, so you always know why a line was drawn. Short gaps of 2-3 days are bridged with dashes; longer gaps are left honest.

■ Ovulation estimate & cycle stats The day before the shift is shown as the estimated ovulation day. Average cycle length and luteal-phase length over the last six cycles are computed automatically.

■ Print layout for clinic visits Preview a clean A4 white-background table (date, cycle day, temperature, period, notes) you can show your gynecologist as-is.

■ CSV export Take your data anywhere as CSV (Excel-ready, UTF-8 with BOM).

■ Built for peace of mind

• Fully local: data stays on your device. No account, no server
• No analytics SDK; your records are never sent to the ad SDK
• Atomic writes - designed above all so records never vanish
• Deliberately no Bluetooth thermometer sync (no sync failures, ever)

■ Pricing Unlimited history, charts, shift detection, cycle stats, printing, and CSV are all free. "Remove Ads" ($0.99 one-time, no auto-renewal) only hides the banner ad.

■ Disclaimer This app provides general reference information only. It does not diagnose pregnancy or provide contraception guidance. Please consult your gynecologist.