Why your tax code might change

First of all, if you happen to get married, or something similar like a civil partnership or indeed on a less happy note if you were married and get separated then it might be that the tax code will change.

Or if you start to get a second income on top of your main income, lucky you, then it is likely that your tax code will need to change and so HMRC should be informed of this.

Also if the levels of untaxed income you receive goes up or down then it might be that the tax code will also be affected.

What happens if your code is wrong of course is that you pay too much or too little tax; you get a notice when your tax code changes.

Of course, these things can be adjusted when the right code is put in place and you can make up the excess or get paid an excess accordingly but it is always best to check whether a change in your situation might change your tax code and ensure that the appropriate steps are taken to inform those who need to know.