Unplanned; not scheduled — something not included in prior plans or schedules.
計画外の出費で今月の貯金が減ってしまった。
Unexpected expenses reduced my savings this month.
旅行中に計画外の雨に降られて、予定を変更した。
We were hit by unexpected rain during the trip and had to change our plans.
計画外に休暇を取ることになったので、上司に連絡した。
I ended up taking unplanned leave, so I contacted my boss.