Apparatus for measuring belts, comprising: a first rangefinder (S 1 ) making first distance measurements from the first rangefinder to a belt having a regularly spaced topographical feature and advancing at a belt speed in a direction of belt travel transverse to the distance between the first rangefinder and the belt; a processor receiving the first distance measurements from the first rangefinder (S 1 ) and producing a first profile record (D 1 ) of a predetermined number of sequential first distance measurements; a second rangefinder (S 2 ) making second distance measurements from the second rangefinder (S 2 ) to the belt , wherein the second rangefinder (S 2 ) is offset from the first rangefinder (S 1 ) in the direction of belt travel by a separation distance (d s ); wherein the processor receives the second distance measurements, produces a second profile record (D 2 ) of a predetermined number of sequential second distance measurements; wherein the processor is configured to determine the distance between consecutive positions of the regularly spaced topographical features on the belt from the belt speed and either: (a) an auto-correlation time delay (τ p1 ') between consecutive occurrences of the regularly spaced topographical feature in an auto-correlation (R 11 ) of the first profile record (D 1 ); or (b) a cross-correlation time delay (τ p ) between consecutive occurrences of the regularly spaced topographical feature in a cross-correlation (R 12 ) of the first profile record (D 1 ) and the second profile record (D 2 ). a first rangefinder (S 1 ) making first distance measurements from the first rangefinder to a belt having a regularly spaced topographical feature and advancing at a belt speed in a direction of belt travel transverse to the distance between the first rangefinder and the belt; a processor receiving the first distance measurements from the first rangefinder (S 1 ) and producing a first profile record (D 1 ) of a predetermined number of sequential first distance measurements; a second rangefinder (S 2 ) making second distance measurements from the second rangefinder (S 2 ) to the belt , wherein the second rangefinder (S 2 ) is offset from the first rangefinder (S 1 ) in the direction of belt travel by a separation distance (d s ); wherein the processor receives the second distance measurements, produces a second profile record (D 2 ) of a predetermined number of sequential second distance measurements; wherein the processor is configured to determine the distance between consecutive positions of the regularly spaced topographical features on the belt from the belt speed and either: (a) an auto-correlation time delay (τ p1 ') between consecutive occurrences of the regularly spaced topographical feature in an auto-correlation (R 11 ) of the first profile record (D 1 ); or (b) a cross-correlation time delay (τ p ) between consecutive occurrences of the regularly spaced topographical feature in a cross-correlation (R 12 ) of the first profile record (D 1 ) and the second profile record (D 2 ). (a) an auto-correlation time delay (τ p1 ') between consecutive occurrences of the regularly spaced topographical feature in an auto-correlation (R 11 ) of the first profile record (D 1 ); or (b) a cross-correlation time delay (τ p ) between consecutive occurrences of the regularly spaced topographical feature in a cross-correlation (R 12 ) of the first profile record (D 1 ) and the second profile record (D 2 ). <EOS>