miscalculate

mis- +‎ calculate

miscalculate (third-person singular simple present miscalculates, present participle miscalculating, simple past and past participle miscalculated)

1. To calculate incorrectly.

   They miscalculated by assuming the dimensions were in imperial, not metric.

2. To make a gross error in judgement.
   • 1950 September 1, Harry S. Truman, 2:37 from the start, in MP72-73 Korea and World Peace: President Truman Reports to the People‎, Harry S. Truman Presidential Library and Museum, National Archives Identifier: 595162:

     Hitler and the Japanese generals miscalculated badly, 10 years ago, when they thought we would not be able to use our economic power effectively for the defeat of aggression. Let would-be aggressors make no such mistake today.

   • 2023 August 9, Nigel Harris, “Comment: Disinterested and dishonest”, in RAIL, number 989, page 3:

     Obsessed only with cost, 'Sir Humphrey' saw that Transport for London 'got away' with ticket office closures on the Tube with only minor public pushback and miscalculated that it could do the same on the national network. This assumption backfired spectacularly.