Miscalculation (noun)

1. An incorrect calculation or estimate.
2. A mistake in judgment or assumption that leads to a wrong result.

Origin:

From 'mis-' meaning 'incorrect' and 'calculation' meaning 'the process of determining something by mathematical methods'.

Examples:

1. The miscalculation led to a large financial loss.
2. The miscalculation was a costly error.
3. The miscalculation was the result of a simple mistake.
4. The miscalculation was discovered too late.
5. The miscalculation was the cause of the failure.