AN & NPT Thread Sizes Chart

AN Thread SizesNPT Thread Sizes
AN SizeTube SizeThreadPipe SizeThreads/Inch
– 21/8″5/16 – 241/1627
– 33/16″3/8 – 241/827
– 41/4″7/16 – 201/418
– 55/16″1/2 – 203/818
– 63/8″9/16 – 181/214
– 81/2″3/4 – 163/414
– 105/8″7/8 – 14111 1/2
– 123/4″1 1/16 – 121 1/411 1/2
– 161″1 5/16 – 121 1/211 1/2
– 201 1/4″1 5/8 – 12211 1/2
– 241 1/2″1 7/8 – 12  
– 281 3/4″2 1/4 – 12  
– 322″2 1/2 – 12  
Tube size is indicated in 1/16″
Examples:
1AN = 1/16″
4AN = 4/16″ = 1/4″
6AN = 6/16″ = 3/8″