miscalculate
Definitions
To calculate or estimate incorrectly.
To judge a situation or outcome wrongly.
Examples
It is easy to miscalculate the amount of paint needed for a room of this size.
The architect did not want to miscalculate the structural load of the bridge.
If you miscalculate your travel time, you will likely miss your flight.
Synonyms
misjudge err miscompute misreckon blunder misestimate misinterpret