JIS dimension tables in English
Dimension tables of Japanese Industrial Standards (JIS) flanges, in millimetres. This site is run in Japan.
This English section is new. For now, it has only the flange tables for 5K to 20K. Tables for steel pipes and O-rings will follow.
Tables
Flanges
- JIS 5K flange18 sizes, 10A to 300A.
- JIS 10K flange18 sizes, 10A to 300A.
- JIS 16K flange16 sizes, 10A to 300A (no 175A or 225A).
- JIS 20K flange16 sizes, 10A to 300A (no 175A or 225A).
Each flange table also gives estimated bolt lengths and gasket sizes.
How the values are checked
Every JIS value on these pages was read twice, independently, from a copy of the original JIS (Japanese text). We also compared the values with 7 published sources from manufacturers and other companies.
Details of the checks
- We read each JIS table from a copy of the original JIS (Japanese text) found on the internet. A second reading, done separately, was compared with the first. We did this for every JIS value on these pages in October 2026.
- We compared these 7 sources with this site's values by 6 October 2026. A publisher is counted once for each kind of table, such as flanges or gaskets. We found wrong values in 4 table cells of these sources. In these comparisons, we have not found an error in this site's JIS values.
- The JIS copies that we read are not published by JISC (Japanese Industrial Standards Committee). We have not yet checked the values against a copy bought from JSA (Japanese Standards Association). JSA sells the standards, and English translations are available for many of them.
- Values that this site calculates, such as bolt lengths, are marked as estimates on each page.
- We use generative AI for research, for reading and comparing the JIS tables, and for writing code. The results are checked as described above.
Japanese site
The Japanese site has calculators and more tables (Japanese only).
Open the Japanese site