WordNet sense 1 (a document appraising the value of something (as for insurance or taxation)):

appraisal, estimation

WordNet sense 2 (an approximate calculation of quantity or degree or worth):

approximation, idea

WordNet sense 3 (judge to be probable):

calculate, figure, forecast, reckon, count on

WordNet sense 4 (judge tentatively or form an estimate of (quantities or time)):

gauge, guess, judge, approximate, approximate