What it is

Inner Day is a rhythm companion for people with Non-24-hour sleep-wake rhythm. When your body clock drifts later every day, “what time is it” stops meaning much: ordinary alarms never wake you, and schedules never line up. Inner Day takes a different approach — instead of living by the calendar day, you live by your body day. It analyzes your free-running period from long-term sleep observations and converts each calendar day into your body time, so alarms, schedules, and reminders follow your rhythm rather than the calendar.

There is no account and no tracking: health data is read-only and processed on-device, and everything stays on your device and in your own iCloud.

Who it is for

People with Non-24-hour sleep-wake rhythm, and night-oriented sleepers whose rhythm free-runs or is markedly delayed
Observers who want to know exactly how long their rhythm runs, which way it drifts, and how fast
People who need to show their physician what is happening — the 28/60-day and custom (up to 90-day) evidence-based reports export to PDF / CSV
Family members and caregivers: track a loved one’s rhythm, and explore everything in demo mode without any data

Key features

Body-day clocking: automatic free-running period analysis from long-term sleep observations (with 95% confidence intervals), or a manual 18–36 hour period with a body-midnight anchor; Home Screen and Lock Screen widgets show your current body time at a glance
Rhythm forecast & Golden Awake Window: see how much your predicted sleep window overlaps ordinary daytime hours (aligned / partially shifted / flipped); the Golden Awake Window compares predicted sleep against your target awake hours on dual 24-hour timelines, so you can lock in dates for outings, appointments, and shift swaps (3 / 14 / 30 days ahead)
Apple Health integration: reads sleep (including REM / core / deep stages), daylight time, steps, and active energy — read-only and processed locally, never written back; log sleep manually on nights without a watch
Sleep details & trends: day-by-day sleep-stage timelines, weekly / monthly / 6-month trend breakdowns and average total sleep, with manual corrections
Evidence-based reports: 28 / 60-day and custom (up to 90-day) observation reports with key metrics, influencing factors, and data-quality notes, exportable as full PDF, charts PDF, and CSV; copy the one-page Visit Summary as text, or share your current rhythm as a Rhythm Status Card image
Body-time alarms & reminders: AlarmKit-powered system alarms ring at your body time — even in silent and focus modes; quick presets by body phase, plus wind-down and wake-light phase-transition reminders delivered as a notification or system alarm
Schedule conversion: reads calendar events and converts them into your body time (read-only; never writes to your calendar); reference sleep projections now extend 30+ days ahead
Home Screen & Lock Screen widgets: body time, rhythm phase, and multi-day sleep windows right on your home screen; widget language follows your in-app setting
Data & backup: full JSON backup and restore anytime (free); members can enable iCloud sync or upload iCloud Drive restore points, with a local-vs-cloud diff preview before restoring

Free vs. membership

Recording, observation, and local backups are free. The free tier includes viewing and exporting 28-day reports in every format (PDF with a light footer watermark), 1 body alarm, 3 manual schedules, the Golden Awake Window for the next 3 days, and a 2-day drift preview. Membership unlocks unlimited body alarms and manual schedules, 14 / 30-day Golden Awake Windows, the full multi-day drift preview, 60 / 90-day and custom-range reports with watermark-free export, system-alarm delivery, calendar import, customizable home cards, Rhythm Status Card sharing, and iCloud sync & Drive backup uploads. Available as a monthly subscription, yearly subscription, or a one-time lifetime purchase; prices as shown in the app.

Why we built it

Non-24 is a rhythm few people understand: society runs on 24 hours, and your body does not. Existing tools are either clinical instruments for physicians or assume everyone lives by the calendar. We wanted a dignified tool for this state — one that does not try to “fix” you, but helps you stay organized anyway: know what body-time it is right now, when you are likely to sleep, when you will wake, and bring a data-backed report to your appointments. A tool cannot pull your rhythm back to 24 hours — but it can keep any given day from being chaos.