Pakistani Banks are using different Account Formats. However, the standard format is 24 Character. Pakistani Banks need to improve a lot to sort this problem. The UK being a financial hub and innovator has resolved this method in a very good way. Let me explain to you UK Approach to IBAN and Bank Account with reference to Faysal Bank Pakistan.
For Example: PK33FAYS3088301000002775
This is a standard format but it is a bit difficult to communicate with others. There is an easy way to break it down and it can work very well in Pakistan. According to the UK rules above IBAN, it can be formatted like this.
In the UK people only share 883010 (Branch Code) & 00002775 (Account No.) If Pakistani Banks start following these procedures, it will make customers life easy.