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.

today's rhythmpower day
87/100
phys
+92
emo
+74
int
+61
itu
+88
your wave · 30 days
today's brief
Move loud at 4pm. Skip small talk.
12may
next power day
Quad-peak in 8 days.
today's log
slept 8h, lifted heavy+92
felt buzzy, social+74
today
forecast
log
you
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.

04in 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.

05pricing

free to feel it.
pro to plan with it.

Free forever for one person, no card required. Pro pays for itself the first week it moves a hard conversation off a bad day.

free
£0forever
  • Your wave, live
  • Daily rhythm score
  • Journal + mood log
start free
proSave 44%
£39.99/year
or £5.99/month
  • AI daily briefings
  • Full 90-day forecast
  • Calendar feed + push
  • Everything in free
start free · upgrade in-app
family
£59.99/year
  • Pro for the whole household
  • Everyone's wave, one screen
  • Plan around shared power days
start together

no card to start · cancel anytime · prices in gbp

06ready 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