A sheet length detector with skew compensation for use in apparatus for batching and counting currency, food stamps or the like. Sheets are advanced past a pair of sheet sensors which are disposed at transversely spaced locations on the feed path on either side of the nip formed by a pair of opposing feed members. A timing interval is begun upon the actuation of both sheet sensors and ended upon the deactuation of both sensors following their initial actuation. The duration of the timing interval provides a measure of sheet length. This measure is then corrected for skew, which is determined from the time lapse, if any, between the deactuation of one sensor and the deactuation of both sensors. The corrected measure may be compared with an absolute reference or with the results of a previous length measurement.