(けいさんちが)

けいさんちがい
noun
miscalculation; error in judgment
1. miscalculation; arithmetic error
A mistake in a mathematical calculation or numerical computation.
計算違(けいさんちが)いがあった。
There was a miscalculation.
見積(みつも)りに計算違(けいさんちが)いがないか確認(かくにん)した。
I checked the estimate for calculation errors.
予算(よさん)計算違(けいさんちが)いがあり、費用(ひよう)大幅(おおはば)超過(ちょうか)した。
There was a miscalculation in the budget, and costs significantly exceeded the plan.
2. misjudgment; wrong estimate; things not going as planned
A figurative miscalculation — when a plan, prediction, or expectation turns out to be wrong.
それは計算違(けいさんちが)いだった。
That was a misjudgment.
相手(あいて)(あま)()たのが計算違(けいさんちが)いだった。
Underestimating the opponent was a miscalculation.
計画(けいかく)順調(じゅんちょう)だったが、天候(てんこう)変化(へんか)計算違(けいさんちが)いだった。
The plan was going well, but the change in weather was something I hadn't accounted for.

Composed of 計算(けいさん) (calculation) + (ちが)い (difference/mistake). The figurative sense (misjudgment, things not going as planned) is more common in everyday conversation than the literal arithmetic sense.

COMMON PATTERNS:

  • 計算違(けいさんちが)いだった: it was a miscalculation
  • 計算違(けいさんちが)いがあった: there was a miscalculation
  • 〜が計算違(けいさんちが)いだった: ~ was something I hadn't accounted for

USAGE:
Often used when someone's plan fails because they underestimated something or didn't anticipate a factor. The tone implies a mistake in judgment rather than a simple arithmetic error.

SIMILAR WORDS:

  • 誤算(ごさん): miscalculation, misjudgment (slightly more formal, similar meaning)
  • 見込(みこ)(ちが)い: wrong estimate, misjudgment
  • ()(ちが)い: misreading (of a situation)