1. an error in calculating or estimating a number, amount, or result
2. a failure to judge or assess a situation correctly, leading to an unintended consequence

Examples

• The accountant's miscalculation resulted in an incorrect tax return.
• A strategic miscalculation led the company to lose millions in the failed merger.
• The engineer caught a miscalculation in the bridge design before construction began.
• His miscalculation of the distance caused him to miss the jump.
• The general's miscalculation of enemy strength proved costly in battle.
• A simple miscalculation in the recipe ruined the entire batch of cookies.