The assessment period for Universal Credit is one month.
Your entitlement to Universal Credit depends on your circumstances and your income in each complete assessment period.
Your first assessment period for Universal Credit usually starts 7 days after you claim; these are called waiting days. You do not receive your first payment of Universal Credit until after the first assessment period has ended. You will then receive the next payments of Universal Credit after each subsequent assessment period on the same date of the month.
If you are unable to work due to illness or disability, you may want to check the Employment and Support Allowance Benefit Guide or the Universal Credit Benefit Guide to read about the assessment phase.