Know Her vs
Stardust
Stardust wants to talk about the moon. You just want to know how she's doing today.
★ Practical, not astrological
Stardust wants to talk about the moon. You just want to know how she's doing today.
Stardust blends her actual cycle data with moon phases and astrology. If you want signal, not horoscope, that's a real problem.
Stardust tracks her period alongside moon phases and astrology content, and lets her invite people into her "orbit" — friends, family, or a partner, all treated the same way. To its credit, joining her orbit costs you nothing, and if she's into astrology, it's a genuinely well-built app for that combination. But it's built for sharing her experience with whoever she chooses, not for helping a man figure out what she needs from him. Know Her asked a different question from day one: what does the man actually need to know? The language, the phases, the widget, the daily tip — all built for that, with zero horoscope content getting in the way of an actual answer.
Before you see a single thing, this has to happen first.
You're a guest in her orbit, watching alongside her friends and family — not someone the app was built to actually help.
No account from her. No invite, no orbit. Know Her is fully yours, from day one — 100% offline, locked behind Face ID if you want.
Know Her vs Stardust, side by side.
| Know Her | Stardust | |
|---|---|---|
| Built for male partners | ✓ Purpose-built | Women's app with a partner invite |
| Requires action from her | ✓ No — you do it yourself | ✗ She must invite you |
| Works if she stops tracking | ✓ Yes — predictions are yours | ✗ No — depends on her logging |
| 100% offline | ✓ Yes | ✗ Cloud-based |
| No account needed | ✓ Yes | ✗ Requires a Stardust account |
| Home screen widget | ✓ Yes | ✗ No |
| Phase-change notifications | ✓ Yes — day before | Not built for the invited partner |
| Face ID / biometric lock | ✓ Yes | ✗ No |
| Private notes on the calendar | ✓ Yes — offline, only yours | ✗ No |
| Language designed for men | ✓ Plain, practical | Astrology and wellness terminology |
| Predictions self-calibrate | ✓ Yes — learns her cycle | Reflects her logged data |
| Your price | $2.99/mo — 14-day free trial | Free to be invited; her Premium is separate |
What the app was built to solve changes everything about how it works.
Where your data lives is a design decision, not a technicality.
Know Her stores everything on your device. Period history, notes, settings — none of it is uploaded anywhere. There is no server holding her cycle data. You can lock the app behind Face ID, and the data stays entirely yours.
Stardust runs through its own cloud infrastructure, and the orbit/partner feature syncs her data to whoever she invites. Your access to her cycle information is mediated by her account, her sharing choices, and an internet connection on both sides — a different kind of relationship with sensitive health information than data that never leaves your device.
What it actually costs as a couple.
Then $19.99/year (or $2.99/month). One app, one subscription — yours. No other accounts or plans required. Cancel anytime.
Being invited to her orbit is free, but her own accurate tracking sits behind Stardust Premium. Know Her requires no subscription from her at all.
A subscription that's entirely your own — nothing riding on what she pays for.
About choosing between Know Her and Stardust.
See how Know Her stacks up against other apps.
Available on
iOS & Android.
Free for 14 days.
No commitment. Cancel anytime.
