not astrology · this is biology

some days just
hit different.

Drained for no reason? Brain fog out of nowhere, then weirdly unstoppable two days later? It's not random. Since the day you were born, four cycles have been running your energy, mood, focus, and gut. RhythmBio maps all four from your birthday and tells you what today's actually built for.

9:41tue · day 14
good morning, mira

your body's
on a peak.

rhythm scorepower day
87/100
physical
92
emotional
74
intellectual
61
intuitive
88
your wave · 30 days
today's briefing
Most of your cycles point up today. Could be the day for the big thing.
12may
next power day
Quad-peak in 8 days.
today's log
slept 8h, lifted heavy+92
felt buzzy, social+74
today
forecast
family
journal
more
23day physical28day emotional33day intellectual38day intuitive7days to test it
02the four cycles

you're built on
four rhythms.

Since the day you were born, four cycles have quietly run your energy, mood, focus, and gut. They never pause. RhythmBio just shows you where each one's at, today and for the next 90 days.

cycle / 0123d

Physical.

23
day cycle

Energy, strength, how tired you feel. That drained day isn't laziness, your body's just in a dip.

cycle / 0228d

Emotional.

28
day cycle

Mood, patience, social battery. Everything hits harder near the bottom of this one.

cycle / 0333d

Intellectual.

33
day cycle

Focus, memory, decisions. The 'why can't I think today' days live right here.

cycle / 0438d

Intuitive.

38
day cycle

Gut instinct and creativity. Trust the hunch on a peak; sleep on it during a low.

03the wave

the wave is
the math.

Each cycle is a simple sine wave. Layer all four and you get a pattern no one else has: your rhythm for any day, past or future, from a single number, your birthday.

your next 30 days · today centered
physicalemotionalintellectualintuitive
−15d−10−5today+5+10+15d
01

Pure trigonometry.

sin(2π × days_since_birth ÷ period). No surveys, no guesswork. Math.

02

Don't believe us.

We're not asking you to. Log how you actually feel for 7 days and let your own journal tell you whether your wave is real.

03

Predictable, not random.

The same math runs forward and back. Plot 90 days ahead, then test it against your own log.

04

Yours and only yours.

Same birthday twins share a wave. Everyone else has a unique signature.

04what's inside

more than a chart.

Every day, the app actually does something with your numbers, not just show them to you.

01

A briefing, written fresh.

Every morning, an actual paragraph about your day, not a score in a vacuum, using your real cycle positions from that morning.

02

Family Hub coaching.

Add the people you live with. Get relationship-aware plays, age-appropriate conversation starters, and a plain-English playbook for the days someone's cycle is crossing zero.

03

90 days ahead.

See every peak and dip coming weeks out, so the big ask, the launch, or the trip lands on a day built for it.

04

The 7 day test.

Log how you actually feel for a week. Your journal shows how closely real life tracked the prediction, and keeps a streak while you do it.

05

The Sunday recap.

A short email summing up the week that was and the one about to start, so Monday morning isn't the first time you've thought about it.

06

Tomorrow, on your lock screen.

Turn on push and wake up to tomorrow's score before you've even opened the app.

05in the wild

built for real
life.

Not a wellness lecture. Practical tools for the decisions you're already making.

monday morning
01 · planning

Schedule the hard week.

See where your peaks land. Block the deep work, the talks, the asks. Avoid stacking critical days into a low.

5pm
02 · gym

Lift on a physical peak.

Coordination and stamina spike with the 23-day cycle. Hit PRs when the math says yes; rest when it says no.

tuesday 7pm
03 · relationships

Have the talk on a high.

Empathy peaks with emotional cycles. Pick the date on the upswing, for both of you if you're tracking together.

all morning
04 · deep work

Think hard when you can.

Save the strategy doc, the architecture review, the pitch deck for an intellectual peak. Your brain is literally on.

06pricing

free to feel it.
pro to plan with it.

Free forever for one person, no card required. Every new account also gets 7 days of full Pro, on us, so you see what it's like before deciding.

new here? your first 7 days run on Pro, free — no card, no auto-charge
free
£0forever
  • Your wave, live
  • Daily rhythm score
  • Journal + mood log
start free
pro
£4.99/month
or £39.99/year · save 33%
  • AI daily briefings
  • Family Hub for everyone you track
  • Full 90-day forecast
  • Calendar feed + push
  • Everything in free
start free · upgrade in-app

no card to start · cancel anytime · prices in gbp

07ready when you are

ready to feel
less random?

Free forever for one person. Add your birthday, see your next 90 days, and start clocking your own patterns.

start tracking · free →read the science
RhythmBio · 2026not astrology · this is biology