Universal Credit (UC) is worked out each month on the basis of the income you received in the previous month. Therefore if you receive a one-off payment from your employer, it will affect your next month’s Universal Credit. Very large one-off payments will also affect the following one or two months’ UC awards.
In most cases your UC will be reduced by 65% of your net additional payment (ie by 65% of the additional amount you receive, after tax and National Insurance).
You do not have to report the extra income, but it is very important to realise that your Universal Credit will be significantly reduced.
If your income increases so much that you do not receive any Universal Credit payment for one month, you will need to inform the UC office as soon as possible if your income will reduce again the following month. You will also need to confirm any changes of circumstances.
Do this as soon as possible so that your next monthly payment is not delayed.