A 4-Bed House as a Single Let or a 4-Room HMO: The Numbers in 2026

A four-bedroom house can be let whole to one household or room by room to four tenants. Room by room usually brings in more rent. It also moves bills and council tax to you, adds a licence in some areas, and costs money to set up. This guide works through one example with every input shown, then sets out the steps in the order you take them.

Correct as at 22 October 2026. England only.

Disclaimer: This guide is for information only and is not legal, tax or financial advice. The example is an illustration built from published averages and our own stated assumptions. It is not a forecast for your property.

The worked example: one North West house, two ways

The example is a four-bedroom house in the North West of England. Every rent figure is an average for the region, and the house next door to yours could be a long way from it. Put in your own local rents and quotes before you rely on any of this.

The inputs

Two things about these figures matter.

• SpareRoom's room rents include bills. Its index is based on asking prices "inclusive of bills". That is why the bills appear as your cost in the HMO column below.
• The two sources measure different things. ONS covers rents being paid on new and existing tenancies. SpareRoom covers asking rents on rooms advertised now. Asking rents on new lets can run ahead of rents on existing tenancies, so this comparison may flatter the HMO a little.

We used SpareRoom's North West figure, not its UK average of £769 (Q3 2026). The UK average includes London, where rooms average £932, and setting it against a North West house rent would overstate the HMO by £151 a room each month.

Gross income

On rent alone, the HMO brings in £11,580 a year more. A comparison that stops here overstates the gap.

Voids, our assumption

A house is let to one household on one tenancy. An HMO has four tenancies starting and ending at different times. We assume the single let is empty for half a month a year and each room is empty for one month a year.

The costs that move to you in an HMO

In a single let, the tenant normally pays council tax and the bills. In an HMO let room by room, they usually become yours.

Council tax is the line most often missed. Where a house is an HMO, or is let to tenants who each rent only part of it, the owner, not the tenants, is liable for the council tax. An HMO is billed as one dwelling, not one bill per room.

The net comparison

The net uplift is £4,082 a year, or about £340 a month. That is roughly a third of the £11,580 gross difference.

Left out of both columns: mortgage interest, tax, letting fees, routine repairs and certificates. Most of those apply either way. Repairs and wear may run higher with four separate households, which would narrow the gap further.

What moves the answer. Room rent matters most. Each £50 a month on every room changes the yearly uplift by £2,200 (4 rooms × £50 × 11 let months). A higher council tax band, a council with no licensing scheme, or a heavier energy bill each move it by hundreds of pounds.

Thinking about converting? Before you spend anything, list every date the house will carry once it is an HMO, from gas and EICR to the licence. Build your free compliance checklist →

What the conversion costs, and how long it takes to pay back

The build. Renovat Construction, a Manchester builder, puts a mid-specification HMO conversion in the Manchester area at £8,000 to £15,000 per room, and a four-bed conversion without en-suites at £40,000 to £60,000 (2026). That covers works such as fire safety, partitions, electrics and finishes. It excludes planning, licence fees, surveys and furniture. These are a builder's estimates, not survey data, and your house's condition will decide where in the range you land.

Furniture. We assume the rooms are let furnished, at £1,500 a room, or £6,000.

The sum

That is roughly 11 to 16 years on these figures. In an Article 4 area, add the £610 planning fee and any consultant's fees. If you finance the works, add the interest.

This is the honest version of the HMO pitch. The extra rent is real, but much of it goes on running costs, and the setup costs take years to earn back at average rents. The case gets stronger where room rents are well above the regional average, where the house needs little work, or where you can let more rooms. Run the sum with your own figures before you commit.

The steps, in order

The order matters. Some steps decide whether the next is worth paying for.

1. Check planning: C3, C4 and Article 4

Planning law puts a house lived in by a single household in use class C3, and a small HMO of not more than six residents in class C4. A change from C3 to C4 is permitted development: the national General Permitted Development Order grants planning permission for it, so you do not need to apply unless something removes that right. The right does not cover a change that turns one house into two or more separate dwellings.

A council can make an Article 4 direction so that the right does not apply in all or part of its area. Inside that area, you need to apply for planning permission. The national fee for a change-of-use application is £610 from 1 April 2026, and it is uprated every 1 April. Many councils have made Article 4 directions for HMOs. Liverpool's planning page is an example: it maps its Article 4 area and says when you need permission to convert a house in it. Search your own council's site for "Article 4" and "HMO", and check the map against your street.

If you want written confirmation that your proposed use is lawful, you can apply to the council for a lawful development certificate under section 192 of the Town and Country Planning Act 1990.

An HMO for seven or more residents falls outside class C4 and outside that permitted development right, so ask the council whether your change needs planning permission.

2. Check licensing

Mandatory HMO licensing applies where an HMO is occupied by five or more persons living in two or more separate households. A four-room house let to four tenants is below that line. That does not settle it. A council can designate all or part of its area for additional licensing of other HMOs, and for selective licensing, which is not limited to HMOs. Our guide to additional and selective licensing explains how the three schemes fit together and how to check what applies to your address.

3. Measure the rooms

Where an HMO in England is licensed, the licence must require a room used for sleeping by one person aged over 10 to be at least 6.51 m², and by two people aged over 10 at least 10.22 m². A room under 4.64 m² must not be used for sleeping at all. Measure before you design the layout, because a box room that falls short cannot be let as a bedroom under a licence. How floor area is measured, including the rule on low ceilings, is in our guide to HMO room sizes.

4. Building regulations and fire safety for the works

If the works are building work, such as a material alteration, the Building Regulations 2010 require you, before you start, either to give the council a building notice or to apply for building control approval with full plans. The work must meet the requirements in Schedule 1 to the Regulations. Where the Regulatory Reform (Fire Safety) Order 2005 applies to the building, it must be the full-plans route. Ask your council's building control team, or an approved inspector, which route your works need (regulation 12).

Fire safety is where the build and the licence meet. If your council publishes its own HMO standards, read them before the builder prices the job.

5. Apply for the licence, if one is needed

If a licence is needed, apply to the council before the rooms are let. What the application asks for, and the conditions every licence carries, are in our HMO licence guide.

What changes once it is running

A single let is one tenancy, one deposit and one set of dates. Let room by room, the same house becomes four of each, plus a building to look after.

• Four tenancies. Each room's tenancy starts, renews and ends on its own dates.
• A deposit clock per room. Each room tenancy needs its own deposit protection, with its own prescribed information, within 30 days of receiving that deposit. Our guide to letting an HMO room by room covers deposits, rent reviews and notice for each tenancy.
• Bills. Meter readings, tariffs and supplier problems land with you, and so does a cold winter.
• The shared areas. The HMO management regulations require the manager to keep escape routes free from obstruction, and fire alarms and any firefighting equipment in good working order. The kitchen, hallways and stairs need checking between tenancies as well as at them.

If you manage it yourself, you need a system that holds every date for the building and for each room, not a spreadsheet you update when you remember. In LetSorted, building duties such as gas, electrics and the licence are tracked once for the building, and the deposit and rent are tracked for each room. See how LetSorted handles HMOs.

The risks, briefly

• An Article 4 refusal. In an Article 4 area you are asking for permission, and the council can refuse it. Check the area before you buy or pay for drawings, not after.
• Licence conditions. A licence comes with conditions you must keep to, and the council can set the number of people each room may hold. Breaching a licence condition is an offence.
• Letting without a licence you need. Running an HMO that must be licensed without a licence is an offence. Instead of prosecuting, the council can impose a civil penalty of up to £40,000. A rent repayment order for that offence can cover rent for a period of up to 2 years.
• More inspection than before. Just Landlords, an insurer, reported in April 2026 that its Freedom of Information requests to councils showed HMO licence applications rising from 41,162 in 2018 to 57,725, council inspections up 83% and enforcement up 180% over the same period. This is a company's research, it covers councils across the UK rather than England alone, and we have not been able to read the underlying data. It points one way: an HMO is more likely to be inspected than it used to be.

None of these is a reason not to convert. Each is a reason to check before you spend.

Frequently Asked Questions

How much more does a 4-room HMO earn than a single let?

In our North West illustration, four rooms at SpareRoom's Q3 2026 regional average of £618 bring in £11,580 a year more than the whole house at the ONS average of £1,507 a month for a home with four or more bedrooms (September 2026). After voids and the costs that move to the landlord in an HMO, such as council tax and bills, the difference falls to about £4,082 a year. Your own figures will differ, so rerun the sum with local rents and quotes.

Do I need planning permission to turn a house into a small HMO?

Not usually for a change from a family house (use class C3) to a small HMO of up to six residents (class C4), because national permitted development rights grant permission for it. Where your council has made an Article 4 direction covering your street, that right does not apply and you must apply for planning permission. The national fee for that application is £610 from 1 April 2026. Correct as at 22 October 2026.

Does a 4-bedroom HMO need a licence?

Mandatory licensing applies where an HMO is occupied by five or more persons living in two or more separate households, so four tenants on their own are below it. Your council may still require a licence under an additional or selective licensing scheme. Check with the council before you let the rooms. Correct as at 22 October 2026.