Can someone please explain needle gauges?


I just started nursing school and am learning about needle gauges. I know that the larger the gauge, the smaller the diameter. But why is that? If the gauge is large, shouldn't the diameter be larger by association?

Specializes in ICU.

It's just the way metals are measured. Like if you were to go to Hobby Lobby and buy floral wire, it's measured the same way. Copper is measured the same also. It's just the way it is with metal.

Julius Seizure

1 Article; 2,282 Posts

Specializes in Pediatric Critical Care.

MunoRN explained this in a thread once.

"The "Gauge" measurement system is based on a measurement of how much of something it takes to weigh a certain amount. I believe this started with old gun ammunition. For instance, a 12 gauge shot is considered 12 gauge because it takes 12 of them to weigh 1 pound. Smaller shot would require more shot to weigh 1 pound: so it would have a higher number even though it is smaller. "


109 Posts

The previous comments are totally right, it's how a lot of metals are measures. You can also think if it like a fraction. So like the ammunition example 1 shot was 1/12. So the guages are like the bottom number. The larger the number the smaller the diameter.