A resident landlord is someone that rents out part of their home to a “lodger”, while also living there themselves.
If you’re a resident landlord, you might need to submit a Self Assessment tax return by January 31st each year.
However, if what you earn from your lodger is under £7,500 a year, then you don’t need to declare it or do anything – unless you already registered for Self Assessment in a previous year and didn’t tell HMRC that you don’t need to file a tax return anymore. In this case, you need to submit one even if you don’t have any tax to pay.
If what you earn from your lodger is over £7,500, you can claim this amount as a flat allowance – it’s called the “Rent a Room relief”.