A property has real investment potential when three things line up. The rent it can realistically earn covers every cost, including the mortgage at a stressed interest rate and tax, with money left over. Nothing about the building, the lease or the letting rules will eat into that margin. And it is a home you could sell to a wide market later. Judge each property on its own figures, not on the reputation of the area or a hoped-for rise in price.
This guide sets out the checks to make on an individual property in England, using official Cambridge figures where they exist. If you are still deciding where to buy, our guide to the best areas in Cambridge for property investment compares prices ward by ward. Past changes in prices and rents do not tell you what will happen next, so none of the figures below is a forecast.
The rent is what pays for everything else, so work it out first and work it out cautiously. The best evidence is what similar homes nearby have actually let for: the same type, the same number of bedrooms and, ideally, the same street. Advertised rents show what landlords hope to get, not what tenants paid. Lenders take the same view. The Prudential Regulation Authority (PRA) expects buy-to-let lenders to have the expected rent confirmed by an independent valuer, an automated valuation model or an existing tenancy agreement.
For context, the Office for National Statistics (ONS) average private rent in Cambridge in August 2026 was £1,805 a month, up 1.8% on a year earlier. By size it was £1,256 for one bedroom, £1,613 for two, £1,907 for three and £2,656 for four or more. The average for flats and maisonettes was £1,455. The index covers both new and existing tenancies, so it is not a measure of asking rents on new lets.
Two rules from the Renters' Rights Act affect how much you can rely on the rent. When you advertise a property you must state an asking rent, and you cannot accept offers above it. Once a tenant is in, you can raise the rent only once a year, using Form 4A with at least 2 months' notice, and the tenant can challenge an increase above the open market rent. Set your figures on a realistic asking rent, not on a bidding war.
Picture the tenant before you buy. A commuter will check the journey to work, so check it yourself at rush hour. A family will look at schools. If you are thinking about a student let, there is a possession ground that lets landlords relet to students for the new academic year, but it applies only to full-time students on a joint tenancy in a house in multiple occupation (HMO), and you must give notice at the start of the tenancy. A local letting agent can tell you which kinds of home let quickly and which sit empty.
Gross rental yield is the annual rent divided by the purchase price, multiplied by 100. As an illustration only, 12 months of the August 2026 ONS average rent in Cambridge divided by the July 2026 HM Land Registry average price gives about 4.6% across all property types (£21,660 ÷ £475,151) and about 5.8% for flats and maisonettes (£17,460 ÷ £298,575). These are averages before any costs, not the return on a particular home.
If buying the property means you will own more than one home, you will usually pay 5% on top of the normal Stamp Duty Land Tax (SDLT) rates in England. The higher rates are 5% on the first £125,000, 7% from £125,001 to £250,000 and 10% from £250,001 to £925,000. On a flat bought for £298,575, the Cambridge average in July 2026, that comes to £19,857.50. Counting the tax as part of the cost brings the illustrative gross yield on that flat down from about 5.8% to about 5.5%, before legal fees, a survey and any mortgage fees.
Net yield is the annual rent minus the annual running costs, divided by the total cost of buying, multiplied by 100. The PRA lists the costs buy-to-let lenders should consider, and it is a sensible checklist for your own sums:
If you are borrowing, take off the mortgage interest and the tax as well, then compare what is left each year with the deposit and buying costs you put in. That return on your own cash is the figure that tells you whether the property works for you.
You need a buy-to-let mortgage, or your lender's permission if you plan to let a home that already has a residential mortgage. Lenders test whether the rent can carry the loan if rates rise. The PRA expects the lenders it regulates to:
When the PRA set these standards in 2016, it said the industry standard was a minimum ratio of 125%, meaning the rent must be at least 125% of the stressed interest. This is industry practice, not a PRA rule, and the Bank of England says lenders tend to use 145% for higher rate taxpayers. The PRA stress test does not cover rates fixed for five years or more, or non-bank lenders. Lenders can set a higher ratio. As an illustration, at 125% and a stressed rate of 5.5%, each £1,000 of monthly rent supports about £174,500 of interest-only borrowing. On those assumptions, a Cambridge flat renting at the £1,455 average would support about £254,000, against an average flat price of £298,575. That is the most generous case. At 145% the figure per £1,000 of rent falls to about £150,500, and on a two-year fix at 5%, stressed to 7%, it is about £137,000 at 125%. A higher stressed rate or ratio means a smaller loan and a bigger deposit. Borrowers with four or more mortgaged buy-to-let properties are treated as portfolio landlords and face more detailed checks.
The Bank of England held Bank Rate at 3.75% on 17 September 2026, and its next decision is due on 5 November 2026. Bank Rate affects other interest rates, including mortgage rates, so test your figures at the rate you might pay when a fixed deal ends, not only at today's rate. Our independent mortgage advice page lists two independent brokers we recommend, who can tell you what lenders will offer on a specific property.
Individual landlords pay Income Tax on their rental profit. Since April 2020 you cannot deduct residential mortgage interest from rental income. Instead you get a tax reduction worth 20% of the lowest of your finance costs, your property profits and your income above the personal allowance. It cannot create a refund, and any amount you cannot use is carried forward. In practice, on profit in the higher rate band you pay 40% on the profit before interest but get only 20% of the interest back.
Two changes start in the 2027 to 2028 tax year. For taxpayers in England and Northern Ireland, property income will be taxed at 22%, 42% and 47%, two percentage points above the current basic, higher and additional rates of 20%, 40% and 45%. The Scottish Parliament and the Senedd set the property income rates for Scottish and Welsh taxpayers. The finance cost reduction will be given at the new property basic rate of 22%. So £10,000 of mortgage interest gives a £2,000 tax reduction now and £2,200 from 2027 to 2028, whatever rate you pay, as long as your property profits and income are high enough to use it.
Landlords with qualifying income from property and self-employment over £50,000 have had to use Making Tax Digital for Income Tax since 6 April 2026, keeping digital records and sending HMRC quarterly updates. The threshold falls to £30,000 from 6 April 2027 and £20,000 from 6 April 2028.
The interest restriction does not apply to companies, which is why some investors buy through a limited company. Companies pay the higher SDLT rates too, and a company buying a home for more than £500,000 may pay a 17% rate instead. Company ownership has its own tax and mortgage rules, so take advice before choosing it.
When you sell a property you have not lived in, you may pay Capital Gains Tax on the gain. For the 2026 to 2027 tax year, higher and additional rate taxpayers pay 24%. Basic rate taxpayers pay 18% on any part of the gain that falls within the basic rate band once it is added to their taxable income, and 24% on the rest. The tax-free allowance is £3,000. You must report and pay any tax due within 60 days of completion. Our guide to the tax you pay when you sell a rental property explains how the gain is worked out.
A low price can hide a large bill. Find out the age and condition of the roof, the boiler and flue, the wiring, the windows and any signs of damp, and get a survey that suits the age and type of property. As a landlord you must keep the home safe and free from health hazards, arrange an annual gas safety check by a registered engineer, have the electrics checked at least every 5 years by a qualified person, and fit smoke and carbon monoxide alarms. Councils can inspect rented homes against 29 hazard areas and can issue an improvement notice, or do the work and bill you, if they find a serious hazard. Price any work in before you make an offer.
Look up the property's Energy Performance Certificate (EPC) on the government register before you view. Most private lettings currently need a rating of E or above. The government intends to raise the minimum to the equivalent of EPC C by 1 October 2030, which still needs new legislation. Its plans include raising the cost cap to £10,000, with exemptions lasting 10 years, and homes rated C or above on an EPC issued before 1 October 2029 would count as compliant until that certificate expires. If a property is rated D or below, find out what it would cost to bring it to C and include that in your figures.
Check the long-term flood risk for the address on the government's flood risk service, which covers rivers, surface water, reservoirs and, where data exists, groundwater. Ask about buildings insurance before you commit.
Many investment flats are leasehold. Before you offer, find out how many years are left on the lease, what the ground rent is and how it rises, what the service charge is and what it covers, and whether the lease allows subletting or needs the freeholder's consent. Ask a mortgage adviser what lease length lenders will accept. A lease with 80 years or fewer left currently costs more to extend, because the price includes "marriage value".
Leasehold law is changing in stages:
Base your offer on the law as it stands, not on savings that may come later.
The Renters' Rights Act changed private renting in England on 1 May 2026, and the changes affect how easily you could get out of an investment:
If you might want to sell within a couple of years, think about whether you would sell with the tenant in place. If you are buying a home that is already let, ask for the tenancy agreement, proof that the deposit is protected, and the gas and electrical safety records.
Other duties continue. You must protect the deposit in a government-approved scheme within 30 days and check that tenants have the right to rent. In Cambridge, a property let to five or more people forming two or more households needs an HMO licence from Cambridge City Council. For applications due between 1 April 2026 and 31 March 2027 the fee is £1,133, or £1,000 if you renew at least eight weeks before your current licence expires. Our lettings service for landlords can help you keep up with these rules.
Nobody can reliably call the bottom or top of the market. On the UK House Price Index, the average price in Cambridge was £475,151 in July 2026, unchanged on a year earlier and 8.9% below its November 2022 peak of £521,404. The average flat price was 2.3% lower than a year earlier. With prices flat, a Cambridge buy-to-let depends mainly on rental income held over a long period, so buy a property whose figures work on today's rent and today's costs.
Our lettings team offers property investment advice in Cambridge and can give you a rental estimate for a specific Cambridge property before you commit.
This article is general information, not financial, tax or legal advice. Speak to a regulated mortgage adviser, a tax adviser or a solicitor about your own circumstances before you invest.
Gross yield is the annual rent divided by the purchase price, multiplied by 100. Net yield takes the annual running costs off the rent and divides by the total cost of buying, including Stamp Duty and fees.
If you will own more than one home, you usually pay 5% on top of the normal rates in England. On a £298,575 flat that is £19,857.50 in total.
Not as a deduction. Individual landlords get a tax reduction of 20% of their finance costs, subject to limits, rising to 22% from the 2027 to 2028 tax year. Companies are not affected by the restriction.
Mainly whether the rent covers the interest at a stressed rate. For rates fixed for less than five years, PRA-regulated lenders test at the higher of 5.5% and a 2 percentage point rise. Most want rent of at least 125% of the stressed interest, or about 145% for higher rate taxpayers.
The years left on the lease, the ground rent and how it rises, the service charge and whether the lease allows subletting. Since 31 January 2025 you can start a legal lease extension without owning the flat for two years first.
