How much should my rent be?

The common rule of thumb is about 30% of take-home pay, and most referencing agents want annual income of at least 2.5 times the annual rent (so a £1,000 monthly rent asks for roughly £30,000 a year). Neither is law. In London and other expensive cities many tenants pay 40% or more, which is a reason to check that the rent is at least in line with the local market — the check above does that.

By any affordability guide, yes, but affordability and fairness are different questions. A rent can be unaffordable for you and still be the going rate for the area, in which case the answer is a cheaper home or a smaller one. If it is above the going rate as well, you have grounds to negotiate it down, and for a formal increase, to challenge it.

There is no fixed percentage in England. A landlord can propose a new rent once a year by Section 13 notice, with at least two months' notice, and the only legal limit is open market rent: what similar homes let for locally. An increase that keeps you inside the local range is hard to resist; one that takes you above it can be referred to the First-tier Tribunal before it starts.

Roughly the same for roughly the same home. Differences in bedrooms, condition, furnishing and floor justify differences in rent; the fact that you moved in later, or that your landlord's mortgage went up, do not. The checker gives you the area range; a neighbour's rent is one more comparable to put beside it.

For the market question, yes: this page. Enter the postcode, bedrooms and a rent figure and it places that figure against the ONS range for similar homes in the area, for England. For the affordability question the arithmetic is simple enough to do by hand: take-home pay multiplied by 0.3 gives the conventional ceiling; the table below has worked examples.