Hi Noble from what you say you are already on joint assessment just with a single income rather than 2 incomes so the rule about changing your basis of assessment doesn't apply as you are not actually changing basis of assessment and it's not your year of marriage either. Your wife can get the extended rate band which keeps up to 24800 of her income at the 20% rate so no need to touch your rate band and she will be entitled to the paye credit of 1650. if you were receiving the home carer credit based on your wife having no or low income and caring for children or elderly parents then you will lose your entitlement to this credit as you as a couple can't avail of both the home carer credit and the extended rate band, this will possibly mean you both being put on a week 1/month 1 basis for the rest of this year. Best to ring revenue with the details of your income this year to date to hand (including paye and usc paid to date) and tell them how much your wife expects to earn this year and in a full year and talk through the options with them (or email them via my account).