All four Pinnacles are built from three numbers — your birth month, your birth day, and your birth year — each reduced to a single digit (or master number) first.
The arithmetic is straightforward. P1 (the First Pinnacle) is the reduced month plus the reduced day. P2 is the reduced day plus the reduced year. P3 is P1 plus P2, reduced. P4 is the reduced month plus the reduced year. Reduce each total to a single digit unless it lands on 11, 22 or 33, which most readers preserve as master numbers.
Worked example. Born 14 March 1991. Month: 3. Day: 14 → 1 + 4 = 5. Year: 1 + 9 + 9 + 1 = 20, then 2 + 0 = 2. So month = 3, day = 5, year = 2. P1 = 3 + 5 = 8. P2 = 5 + 2 = 7. P3 = 8 + 7 = 15 → 1 + 5 = 6. P4 = 3 + 2 = 5. The four Pinnacles for this person are 8, 7, 6, 5 — a building first phase, an introspective second, a domestic third, a restless fourth. Each phase will read differently depending on the Life Path it sits inside.
The timing is also fixed by arithmetic. The First Pinnacle runs from birth to age (36 − your Life Path number). For a Life Path 7, P1 ends at 29. For a Life Path 1, P1 ends at 35. P2 then runs for nine years, then P3 for nine more years, and P4 covers the rest of the life. So for a Life Path 4, the Pinnacles split at age 32, 41, 50, and run from 50 onward.