If you want to end your tenancy when the fixed term period of the agreement is due to run out, you will need to give at least 14 days’ notice. This notice can be given up to and including the last day of the fixed term.
If you want to end your tenancy after the fixed term has ended (and you have not signed another agreement), you will need to give at least 21 days’ notice. This notice can be given at any time and does not have to line up with the rent payment cycle. You must pay the rent up to and including the day your notice ends and you vacate.