Biorhythm calculator and daily analysis
Enter a date of birth to chart eight rhythms, read the analysis for any day and see how the cycles combine. Everything is calculated on your device.
Works offline once installed. See install the app for the steps on your device.
Your details
Nothing you enter leaves this device.
Add a date of birth above to generate the chart and the daily analysis.
Install the app
Add Biorhythm Compass to your Home Screen for offline access.
Select Add app, or use the install icon at the right of the address bar.
Select Add app, then confirm Install in the browser prompt.
If no prompt appears, open the Chrome menu (three dots) and choose Install app.
Choosing Add to Home screen instead of Install creates a shortcut. That shortcut opens a browser tab showing the address with an X, and closing the X closes the whole thing. Delete that icon and use Install app instead.
- 1. Open biorhythmcompass.com in Safari — not Chrome or a link inside another app
- 2. Tap Share
- 3. Choose Add to Home Screen
- 4. Confirm Add, then open Biorhythm Compass from the Home Screen
Added from Chrome or an in-app browser on iPhone, the icon only opens a browser tab with the address and a close button at the top. Safari is the only way to get the full-screen app.
Phones treat the old address and biorhythmcompass.com as two separate apps, so the old icon keeps running the old copy with its own saved profiles.
- 1. Open the old icon and export a backup from My List
- 2. Delete the old icon
- 3. Install this one from biorhythmcompass.com
- 4. Import the backup here
- Opens from the Home Screen without typing an address
- Works offline after the first successful load
- Runs full screen without browser chrome
- Your saved people and settings stay on the device either way
Exact data and methodology
Dates are normalised to whole UTC calendar days, so daylight-saving changes cannot shift a result. Each rhythm value is R(D) = 100 × sin(2πD ÷ P), where D is the number of days lived and P is the cycle period in days.
Direction compares today with tomorrow: more than +3 is rising, less than -3 is falling, and anything between is near a turning point. Phases run from Peak (+85 or above) to Trough (-85 or below).
The daily pattern is chosen from eight named configurations in a fixed priority order, using only the three core rhythms plus a transition count across all eight. Pair relevance is |A| + |B| + 0.35 × |A − B| plus a fixed bonus for the matching pair type.
No artificial intelligence, profiling, probability, astrology or external data is used at any point.
Everything is stored in your browser's local storage under a single key. There is no account, no server and no analytics profile attached to your dates.
Clearing your browser data or the site's storage removes it permanently.
Biorhythm Compass 4.6.1, using Compass Rhythm Synthesis — CRS Algorithm v1.0. When a new version is deployed the app offers an update banner and keeps your saved people, couples and settings.