Important information: 4 flags (2 large and 2 small) are equal to 34.5 inches ( 88 cm). (The flags typically come in groups of four). The small flag is approximately 10.5" x 7.6 " and the large one is approximately 13" x 9.6 ".
You need to know BOTH the number of lanes in your pool AND the width of each lane (or the exact number of feet in the width of your pool). If you only know the number of lanes, we recommend using the wider lane estimate.
How to read this table: Row 1 tells you that for a 6 lane pool with lanes that are each 6 feet wide,
you will need 104 backstroke flags (52 large and 52 small). Six lanes at 6 feet each totals 36 feet for each of the two sets
(74 feet total, or approximately 23 meters total). This requires 104 backstroke flags (52 large and 52 small).
If you only order large flags (instead of 1 large and 1 small) 4 large flags are equal to 38 inches.
If you order only XL flags 4 flags are 4 feet
Above image displays three flag options: an XL flag, a large flag with buttonholes, and a small flag with buttonholes. The buttonholes provide an optional method for securing the flag to a wire or rope using a tie wrap. This can help to reduce flag movement in windy conditions.
Picture showing our backstroke flags during the 1996 Olympic Games in Atlanta
FINA backstroke flag rules
FR 2.2.10 Backstroke turn indicators Flagged ropes shall be suspended across the pool, 1.8 metres above the water surface, from fixed standards placed 5.0 metres from each end wall. Distinctive marks must be placed on both sides of the pool, and where possible on each lane rope, 15.0 metres from each end wall. Flags must be fixed to the ropes having the following dimensions: 0.20 metres on the rope forming a triangle measuring 0.40 metres on the sides. The distance between each flag must be 0.25 metres. If the flags are printed with or support / carry any signage this must be approved in advance by FINA.
Page 15 of link below R 2.2.10 Backstroke turn indicators
https://resources.fina.org/fina/document/2022/02/08/77c3058d-b549-4543-8524-ad51a857864e/210805-Facilities-Rules_clean.pdf