Faucet Thread Measurements

16 mm

16mm = 0.630"

Thread diameter

0.6194"

15.731 mm

5/8"

5/8" = 0.625"

5/8" = 15.875 mm

Thread diameter

0.6205"

15.761 mm

16.5 mm

16.5mm = 0.650"

Thread diameter

0.6446"

16.372 mm

This size is sometimes referred to as "Tom Thumb".   I prefer "16.5mm" myself.

11/16"

11/16" = 0.6875"

11/16" = 17.4625 mm

Thread diameter

0.6842"

17.377 mm

18 mm

18mm = 0.7087"

Thread diameter

0.6932"

17.607 mm

0.7043"

17.888 mm

18.5 mm

18.5mm = 0.7283"

Thread diameter

0.7256"

18.429 mm

This size is sometimes referred to as "Tiny Junior".   I prefer "18.5mm" myself.

3/4"

3/4" = 0.75"

3/4" = 19.05 mm

Thread diameter

0.746"

18.951 mm

0.7488"

19.020 mm

20 mm

20mm = 0.7874"

Thread diameter

0.774"

19.667 mm

13/16"

13/16" = 0.8125"

13/16" = 20.6375 mm

Thread diameter

0.804"

20.418 mm

21.5 mm 

21.5mm = 0.8465"

Thread diameter

0.8336"

21.172 mm

This size is sometimes referred to as "Junior".   I prefer "21.5mm" myself.

0.8342"

21.189 mm

21.5 mm Moen

21.5mm = 0.8465"

Thread diameter

0.8426"

21.402 mm

55/64"

55/64" = 0.8594"

55/64" = 21.828 mm

Functionally identical to 22mm

Thread diameter

0.855"

21.704 mm

22 mm

22mm = 0.8661"

Functionally identical to 55/64"

Thread diameter

0.857"

21.742 mm

15/16"

15/16" = 0.9375"

15/16" = 23.8125 mm

Thread diameter

0.923"

23.448 mm

0.9551"

24.258 mm

Dial Caliper Photos of Measurements

16 mm

16mm = 0.630 inches

16mm threads measure 0.61935 inches

16mm thread diameter

0.619 inches

16mm threads measure 15.731mm

16mm thread diameter

15.731 mm

5/8"

5/8" = 0.625 inches

5/8" = 15.875 mm

5/8" threads measure 0.621 inches

5/8" thread diameter

0.621 inches

5/8" threads measure 15.761mm

5/8" thread diameter

15.761 mm

16.5 mm

16.5mm = 0.6496 inches

5/8" threads measure 0.621 inches

16.5mm thread diameter

0.6446 inches

5/8" threads measure 15.761mm

16.5mm thread diameter

16.372 mm

11/16"

11/16" = 0.6875 inches

11/16" = 17.4625 mm

11/16" thread diameter

0.684 inches

11/16" thread diameter

17.377 mm

18 mm

18mm = 0.7087 inches

18mm thread diameter

0.693 inches

18mm thread diameter

17.607 mm

18.5 mm

18.5mm = 0.7283 inches

18.5mm thread diameter

0.7256 inches

18.5mm thread diameter

18.429 mm

3/4"

3/4" = 0.75 inches

3/4" = 19.05 mm

3/4" thread diameter

0.746 inches

3/4" thread diameter

18.951 mm

20 mm

20mm = 0.7874 inches

20mm thread diameter

0.774 inches

20mm thread diameter

19.667 mm

13/16"

13/16" = 0.8125 inches

13/16" = 20.6375 mm

13/16" thread diameter

0.804 inches

13/16" thread diameter

20.418 mm

21.5 mm

21.5mm = 0.8465 inches

21.5mm thread diameter

0.8336 inches

21.5mm Moen thread diameter

21.172 mm

21.5 mm Moen

21.5mm = 0.8465 inches

21.5mm Moen thread diameter

0.843 inches

21.5mm Moen thread diameter

21.402 mm

55/64"

55/64" = 0.8594 inches

55/64" = 21.828 mm

Functional identical to 22mm

55/64" thread diameter

0.855 inches

55/64" thread diameter

21.704 mm

22 mm

22mm = 0.8661 inches

Functional identical to 55/64"

22mm thread diameter

0.857 inches

22mm thread diameter

21.742 mm

15/16"

15/16" = 0.9375 inches

15/16" = 23.8125 mm

15/16" thread diameter

0.923 inches

15/16" thread diameter

23.448 mm

Hidden Aerator Keys - A different use...

Which thread sizes fit inside which keys?

We can use these keys in a different way: by comparing faucet aerator threads to the inside measurement of these keys!

9/16"

Fits in the yellow key

5/8"

Fits in the green key but not the yellow key

11/16"

Fits in the red key but not the green key

3/4"

Fits in the grey key but not the red key

13/16"

Almost fits in the grey key 

15/16"

Too large to fit in any key

16 and 16.5mm

Fits in the green key but not the yellow key

18 and 18.5mm

Fits in the red key, barely, but not the green key

20mm and larger

Too large to fit in any key