Urological catheters come in a range of sizes that are determined by the measurement of the external diameter of the tube. These sizes are referred to as ‘French sizes,’ which is the universal gauge system for catheters. It is important to know the correct size catheter you need to ensure both comfort and efficiency. Choosing a catheter size that is too small can result in a decreased drainage pace, and/or leakage around the tube during catheterization. On the other hand, using a catheter size that is too large can result in a more painful and difficult insertion.



  • Pediatric catheters usually range from 6-14 Fr and are typically 8 to 12 in long.
  • Female catheters usually range from 8-18 Fr and are typically 6 to 8 in long. The average French sizes for women are 12 or 14 Fr.
  • Male catheters usually range from 8-20 Fr and are typically 16 in long. The average French sizes for men are 14 or 16 Fr.

*Different manufacturers and types may have more sizes available. Foley catheter sizes can also be larger than 24 Fr.