The M. Toulouse Prince of Wales Square Edge 1/2-inch Neck Ladies Spur measures 3/4-inch from boot to tip.
USEF rules state to measure the spur from the base of the spur to the end of the tip. Maximum spur length is 2-inches or 5.08 cm. FEI rules state that the spur can not be longer than 4 cm from boot to end of spur except for FEI Pony Riders and Children are limited to 3.5 cm with no rowels.