www.gov.uk/guidance/universal-credit-advances#how-the-advance-is-repaid
How the advance is repaid
Deductions are made from your monthly Universal Credit payment. The first deduction is made on the day you get your first payment. You must usually pay back the advance within:
24 months if you apply for the advance on or after 12 April 2021 because you’ve made a new claim for Universal Credit
12 months if you applied for the advance before 12 April 2021 because you made a new claim for Universal Credit
6 months if you apply for the advance because of a change of circumstances
You can ask for your repayments to be delayed if you cannot afford them. Repayments can be delayed for:
3 months if the advance is for a new claim
1 month if the advance is for a change of circumstances
This is only allowed in exceptional circumstances.
Cost of repayments
If you apply for an advance online you will be shown on screen the repayment amounts for different repayment periods.
If you apply by phone, the Universal Credit helpline adviser assesses whether you can afford to repay the advance. If they agree to the advance, they will tell you over the phone:
how much you can have
the monthly repayment amounts
when the first repayment is due
www.gov.uk/guidance/universal-credit-advances#how-much-you-can-get
How much you can get
You may be able to get up to 100% of your estimated Universal Credit payment.
You will need to repay an advance from future Universal Credit payments or by other means if you no longer get Universal Credit, such as from wages or other benefits you may be getting.