Here's some readymade regex expressions for a bunch of different [numbers within a certain range][1]:

| Range     | Label        | Regex                                  |
| --------- | ------------ | -------------------------------------- |
| 1 to 12   | hour / month | `1[0-2]|[1-9]`                         |
| 1 to 24   | hour         | `2[0-4]|1[0-9]|[1-9]`                  |
| 1 to 31   | day of month | `3[01]|[12][0-9]|[1-9]`                |
| 1 to 53   | week of year | `5[0-3]|[1-4][0-9]|[1-9]`              |
| 0 to 59   | min / sec    | `[1-5]?[0-9]`                          |
| 0 to 100  | percentage   | `100|[1-9]?[0-9]`                      |
| 0 to 127  | signed byte  | `12[0-7]|1[01][0-9]|[1-9]?[0-9]`       |
| 32 to 126 | ASCII codes  | `12[0-6]|1[01][0-9]|[4-9][0-9]|3[2-9]` |


[1]: https://www.oreilly.com/library/view/regular-expressions-cookbook/9781449327453/ch06s07.html

Regex to allow only number between 1 to 12

 I am trying `(12)|[1-9]\d?` but its not working, please help as i am new to regular expression