Source : Webster's Revised Unabridged Dictionary (1913)

Miscalculate \Mis*cal"cu*late\, v. t. & i.
   To calculate erroneously; to judge wrongly. --
   {Mis*cal`cu*la"tion}, n.

Source : WordNet®

miscalculation
     n : a mistake in calculating [syn: {misreckoning}, {misestimation}]