Circa

Everyone tracks sleep. Nobody fixes it. Circa is a circadian coach, not another sleep tracker. It doesn't hand you a hypnogram and leave you to work it out — it tells you when to get light, when to stop drinking coffee, and when to start winding down, based on where the sun actually is at your coordinates today. WHY YOUR ENERGY IS OFF Most tiredness isn't about hours slept. It's about timing. Morning light anchors your body clock; light at the wrong hour drags it out of place. Caffeine at 4pm is still in your system at midnight. Circa models all of it and turns it into a short daily protocol you can actually follow. WORKS ON A PLANE Solar position, civil twilight and melatonin-onset windows are astronomy — pure maths from your latitude, longitude and the date. Circa computes them on your device using the NOAA solar algorithm. No account, no server, no network needed. Your sleep data never leaves your phone. FREE, FOREVER · Today's full protocol — light window, caffeine cutoff, wind-down, target bedtime · A living sky that mirrors the real sun at your location · Five-second sleep logging · Seven-day sleep debt ledger CIRCA PRO · Unlimited history and trends — months back, not a week · Jet Lag Planner — a day-by-day pre-adaptation plan, built before you fly · Shift-work protocols that don't assume a nine-to-five · Caffeine and meal-timing windows · Energy Forecast — your predicted alertness curve for tomorrow Free stays genuinely useful. Unlimited logging, the full daily protocol and the living sky are free forever. Pro is for depth and time — seeing further ahead, further back, and across timezones. NOT A MEDICAL DEVICE Circa is a wellness tool. It does not diagnose, treat or prevent any condition. If you think you have a sleep disorder, speak to a doctor. Subscriptions renew until cancelled. Manage or cancel any time in Google Play.