The long view of three cycles

Life-Cycle Milestone Chart

Mark birthdays, paired crossings and the rare occasions when all three classic biorhythm cycles meet or fully reset.

Ages 20–30Return to my current decade
18 Oct 2016 to 18 Oct 2026

Your cycle crossings

41markers in this window
Biorhythm milestones between ages 20 and 30Six tracks mark birthdays, paired zero crossings, triple crossings and complete resets. Birthdays Physical + emotional Physical + intellectual Emotional + intellectual All three at zero Complete reset age 20age 21age 22age 23age 24age 25age 26age 27age 28age 29age 30 18 Oct 2016 12:00 — 20th birthday. A personal anniversary marker. 13 Jan 2017 12:00 — Emotional + intellectual. Both cycles cross zero together. 27 Jan 2017 12:00 — Physical + emotional. Both cycles cross zero together. 30 Jul 2017 12:00 — Physical + intellectual. Both cycles cross zero together. 18 Oct 2017 12:00 — 21st birthday. A personal anniversary marker. 15 Dec 2017 12:00 — Physical + emotional. Both cycles cross zero together. 20 Apr 2018 12:00 — Emotional + intellectual. Both cycles cross zero together. 14 Aug 2018 00:00 — Physical + intellectual. Both cycles cross zero together. 18 Oct 2018 12:00 — 22nd birthday. A personal anniversary marker. 2 Nov 2018 12:00 — Physical + emotional. Both cycles cross zero together. 26 Jul 2019 12:00 — Emotional + intellectual. Both cycles cross zero together. 28 Aug 2019 12:00 — Physical + intellectual. Both cycles cross zero together. 20 Sep 2019 12:00 — Physical + emotional. Both cycles cross zero together. 18 Oct 2019 12:00 — 23rd birthday. A personal anniversary marker. 7 Aug 2020 12:00 — Physical + emotional. Both cycles cross zero together. 11 Sep 2020 00:00 — Physical + intellectual. Both cycles cross zero together. 18 Oct 2020 12:00 — 24th birthday. A personal anniversary marker. 30 Oct 2020 12:00 — Emotional + intellectual. Both cycles cross zero together. 25 Jun 2021 12:00 — Physical + emotional. Both cycles cross zero together. 25 Sep 2021 12:00 — Physical + intellectual. Both cycles cross zero together. 18 Oct 2021 12:00 — 25th birthday. A personal anniversary marker. 4 Feb 2022 12:00 — Emotional + intellectual. Both cycles cross zero together. 13 May 2022 12:00 — Physical + emotional. Both cycles cross zero together. 10 Oct 2022 00:00 — Physical + intellectual. Both cycles cross zero together. 18 Oct 2022 12:00 — 26th birthday. A personal anniversary marker. 31 Mar 2023 12:00 — Physical + emotional. Both cycles cross zero together. 12 May 2023 12:00 — Emotional + intellectual. Both cycles cross zero together. 18 Oct 2023 12:00 — 27th birthday. A personal anniversary marker. 24 Oct 2023 12:00 — Physical + intellectual. Both cycles cross zero together. 16 Feb 2024 12:00 — Physical + emotional. Both cycles cross zero together. 16 Aug 2024 12:00 — Emotional + intellectual. Both cycles cross zero together. 18 Oct 2024 12:00 — 28th birthday. A personal anniversary marker. 7 Nov 2024 00:00 — Physical + intellectual. Both cycles cross zero together. 3 Jan 2025 12:00 — Physical + emotional. Both cycles cross zero together. 18 Oct 2025 12:00 — 29th birthday. A personal anniversary marker. 21 Nov 2025 12:00 — Physical + emotional. Both cycles cross zero together. 21 Nov 2025 12:00 — Physical + intellectual. Both cycles cross zero together. 21 Nov 2025 12:00 — Emotional + intellectual. Both cycles cross zero together. 21 Nov 2025 12:00 — Three-cycle zero crossing. Physical, emotional and intellectual cycles meet at zero. 9 Oct 2026 12:00 — Physical + emotional. Both cycles cross zero together. 18 Oct 2026 12:00 — 30th birthday. A personal anniversary marker.
BirthdayTwo cyclesAll three at zeroComplete reset
Emotional + intellectual13 Jan 2017age 20.2 · Both cycles cross zero together.
Physical + emotional27 Jan 2017age 20.3 · Both cycles cross zero together.
Physical + intellectual30 Jul 2017age 20.8 · Both cycles cross zero together.
Physical + emotional15 Dec 2017age 21.2 · Both cycles cross zero together.
Rare whole-life markers

When all three classic cycles meet

Triple crossingAge 29.1

All three classic cycles meet at zero.

Triple crossingAge 58.2

All three classic cycles meet at zero.

Complete resetAge 58.2

All three cycles restart in their original direction.

Triple crossingAge 87.3

All three classic cycles meet at zero.

Crossing versus reset

Zero is a meeting point, not always a restart

Every classic cycle crosses zero twice per cycle: once while rising and once while falling. Two cycles can therefore share a zero crossing without restarting in the same direction.

A three-cycle zero crossing repeats after 10,626 days (about 29.1 years). A complete reset, with all three returning to zero in their original upward direction, repeats after 21,252 days (about 58.2 years).

Difference between a zero crossing and a full resetThree sine waves cross the centre line together, while arrows show that direction determines whether the moment is a full reset.shared zero crossingdirection decides reset
What the mathematics says

Why these dates repeat

Physical + emotional

Their zero crossings coincide every 322 days.

Physical + intellectual

Their zero crossings coincide every 379.5 days.

Emotional + intellectual

Their zero crossings coincide every 462 days.

These are mathematical coincidences within classic biorhythm theory, which is not scientifically established. The chart is for reflection and entertainment, not prediction.

Continue exploring

Move between a single day, a month, a whole year or the longer story of your cycles.

Daily view Biorhythm Calculator Zoom into the physical, emotional and intellectual curves around a chosen day. Month view Personal Calendar Follow the three classic cycles through a focused month-by-month calendar. Two people Compatibility Chart Place two personal patterns together and explore where their rhythms align. Seven rhythms Extended Chart Add intuition, creativity, awareness and spiritual cycles to the classic three.