A Manchester rental valuation depends enormously on which Manchester you mean. The city as a whole currently averages £260,000 to buy and £1,350 a month in rent, a 6.2% gross yield, comfortably above the UK median of 4.1%. That headline number is genuinely good, but it still blends together postcodes that are performing very differently from each other.
The spread within Manchester itself
M14, covering the Fallowfield area near the universities, currently averages an 8.0% gross yield on a £272,000 average asking price and £1,820 average rent, some of the strongest numbers in the city, plausibly reflecting strong student and young-professional rental demand. M33, out toward Sale, averages 3.2%, on a £450,000 average asking price against £1,200 in rent, a much more expensive, lower-yielding suburban market. Both figures meet our minimum sample size before we'll show a yield at all, this isn't noise from a handful of listings.
Manchester as a whole does genuinely well by UK standards, but "Manchester is a good buy-to-let city" and "this specific Manchester postcode is a good buy-to-let area" are different claims, and the gap between the best and weakest postcodes here is wide enough that it matters which one you're actually asking about.
Checking a specific Manchester property
Rather than rely on the city-wide 6.2%, check the full Manchester postcode breakdown for the specific district in question, and run the numbers through the buy-to-let cashflow calculator once you've got a real price and rent to work with.
For how Manchester's own postcodes compare against the rest of the UK, see the highest-yield postcodes nationally.
Figures are gross averages from live market listings as of publication, not a forecast or a valuation of any individual property. Not financial advice.