Hi Kiran Rai
A tax code of 1257L, allows for 1/12 of your personal allowance (12579/12 = 1048) to be set against your employment income each month.
This is added to the next months income and a further 12th added, so that over the full 12 months of a tax year, your personal allowance is alloated in full.
In this way each months should be the same as the last, provided your earnings remain the same. This does not always happen. Sometimes it is necesarry to apply a tax code on a 'month 1' basis.
This means that each month, your earning for that month are treated as though they were from the first month of the tax year and 1/12 of your personal allowance applied.
Each month is treated the same. This can sometime mean that tax is paid, when it is not due.
To have your tax code changed from a month 1 basis to a cumulative basis, will require that you HMRC on 0300 200 3300 or via webchat (
Income Tax: general enquiries), to advise that when you commenced this employment, it was you only employment in the tax year and that you would like a cumulative tax code to be issued to your employer.
Thank you
