HMO Room Size Requirements UK 2026 — Minimum Sizes, Licensing and Penalties

Room size is one of the most commonly breached HMO licence conditions and one of the first things local housing authority inspectors check. A room that was adequate under previous standards may fall below the 2018 minimums. Licensing conditions typically require landlords to measure rooms and provide floor plans to the licensing authority.

Overcrowding in HMOs carries serious penalties. Beyond licensing non-compliance, using a room that is too small for its occupants can constitute a Category 1 hazard under the Housing Health and Safety Rating System (HHSRS), exposing landlords to improvement notices, prohibition orders, and civil penalties of up to £30,000 per offence.

The 2018 minimum room sizes for HMOs in England

The Licensing of Houses in Multiple Occupation (Mandatory Conditions of Licences) (England) Regulations 2018 (SI 2018/221) introduced mandatory licence conditions specifying minimum floor areas for sleeping rooms:

One person aged 10 or over: Minimum 6.51 m² (70 sq ft) of usable floor area
Two persons aged 10 or over: Minimum 10.22 m² (110 sq ft) of usable floor area
One or more persons under 10: Minimum 4.64 m² (50 sq ft) of usable floor area
These apply to all mandatory HMO licences (5+ occupants forming 2+ households) and to any HMO covered by a local additional licensing scheme
The licence must include conditions imposing these minimums — if your existing licence was granted before 2018, it should have been updated on renewal
Local authorities may set higher minimums than the national standards in their licensing schemes — always check your specific licence conditions

What counts as usable floor area?

The floor area calculation excludes areas where the ceiling height falls below 1.5 metres:

Only floor area with a ceiling height of 1.5 m or above is counted as usable floor area
Roof rooms with sloping ceilings: measure only the portion where the ceiling exceeds 1.5 m
Built-in wardrobes and alcoves: generally included if at normal ceiling height and usable
En-suite bathrooms: do not count toward the sleeping room floor area — they are separate rooms
Shared stairwells, lobbies, and communal areas: not counted toward any individual sleeping room
Use a laser measure for accuracy — room sizes are commonly underestimated. Local authorities will measure during inspections

What happens to rooms that are too small?

If a room falls below the minimum floor area, it cannot be used for sleeping accommodation under the licence:

The local authority must be notified — the licence will be amended to exclude or restrict the use of the sub-standard room
The room can be used for non-sleeping purposes (storage, study) while not counting toward occupancy
If a room falls between 4.64 m² and 6.51 m², it can lawfully be used only for sleeping by a child under 10
Rooms below 4.64 m² cannot lawfully be used for sleeping by any occupant
If you continue to let a sub-minimum room as sleeping accommodation, you are in breach of your licence conditions
Breach of mandatory licence conditions is a criminal offence under the Housing Act 2004, carrying unlimited fines on conviction. Civil penalties of up to £30,000 can be imposed without prosecution

HHSRS overcrowding: wider enforcement powers

Beyond licensing, the Housing Health and Safety Rating System (HHSRS) gives local authorities powers to act on overcrowding as a health hazard:

Overcrowding is assessed as a Category 1 or Category 2 hazard under the HHSRS. Category 1 hazards trigger a legal duty on the local authority to take action
An overcrowded room can generate an Improvement Notice requiring the landlord to reduce occupancy or enlarge the room within a specified period
A Prohibition Order can ban any sleeping use of a room until the hazard is remedied
The local authority does not need a licence breach to use HHSRS powers — these can apply to any private rented property regardless of licensing status
Rent Repayment Orders: tenants can apply to the First-tier Tribunal for repayment of up to 12 months' rent where a landlord has been found to have committed an offence under the Housing Act 2004 including licensing non-compliance

How to check compliance for your HMO

Practical steps to ensure your HMO meets room size requirements:

Measure every sleeping room using a laser measure, recording the usable floor area (excluding sub-1.5m ceiling portions)
Draw a simple floor plan showing room dimensions — this is typically required when applying for or renewing an HMO licence
Check your HMO licence conditions: the licence should list the maximum permitted occupancy for each room
If any room falls below 6.51 m², notify your local housing authority and adjust your tenancy arrangements to remove that room from sleeping use
If you discover a room is borderline (e.g. 6.3 m²), do not simply leave it in use — notify the authority and ask for their measurement and assessment
On HMO licence renewal, authorities commonly re-inspect and re-measure. Properties that were previously compliant can fail if measuring methodology changes or if partitions have been installed

Room sizes and fire safety interaction

Minimum room sizes interact with HMO fire safety requirements:

Fire doors must be fitted to all sleeping room doors in HMOs — this does not affect floor area calculation but is a separate mandatory licence condition
Smoke and heat detectors must be interlinked and fitted in each room and communal area
Escape routes must be kept clear — overcrowded rooms with excessive furniture can obstruct escape in a fire, triggering additional enforcement action
Renters' Rights Act 2025: from 1 May 2026 all HMO tenancies auto-convert to Periodic Assured Tenancies. Licence conditions, including room size obligations, carry forward into the new tenancy type unchanged
The Building Safety Act 2022 applies to higher-risk buildings (18m+ or 7+ storeys). HMO landlords of tall buildings face additional duties under the new building safety regime

Frequently asked questions

Does the 6.51 m² minimum apply to all HMOs or only licensed ones?+

The mandatory minimum room sizes set by the 2018 Regulations apply as licence conditions and therefore directly bind HMOs subject to mandatory HMO licensing (5+ occupants, 2+ households) and HMOs in areas with additional licensing schemes. However, even for HMOs that are not subject to licensing (e.g. smaller HMOs outside additional licensing areas), the HHSRS overcrowding provisions still apply. An overcrowded room in any HMO can trigger enforcement action under HHSRS regardless of licensing status. In practice, the 2018 room size minimums have become the de facto national standard referenced by all local housing authorities when assessing HMO fitness.

I have a room that is 6.2 m² — can I use it as sleeping accommodation?+

No. A room of 6.2 m² falls below the minimum 6.51 m² required for sleeping by one adult under the 2018 Regulations. It can only be used for sleeping by a child under 10 (minimum 4.64 m²). You should notify your local housing authority of the room's dimensions and adjust your licence accordingly. The room can be used for non-sleeping purposes (study, storage) without breaching licensing conditions, but it cannot be occupied as a bedroom by an adult or two adults without risk of enforcement. If you continue to use it as an adult sleeping room, you risk a licence breach, HHSRS enforcement, and potential civil penalties.

My HMO was licensed before 2018 — do the new room size rules apply?+

Yes. The 2018 Regulations required local authorities to update existing HMO licences to include the new minimum room size conditions. When your licence was renewed after October 2018, the new conditions should have been included. If you have not had a renewal since 2018 (unusual, as licences are typically 5-year), the conditions still apply as they were imposed by statute on all mandatory HMO licences from that date. Check your current licence document — if it does not reference the 2018 room size conditions, contact your local housing authority for clarification, not because the rules do not apply to you, but because your licence document may need updating.

Can I partition a large room to create two compliant sleeping rooms?+

In principle, yes — if both resulting rooms meet the minimum floor area requirements (6.51 m² each for single occupancy) and each has adequate natural light, ventilation, and fire door access. However, partitioning works in an HMO may constitute a material change of use requiring planning permission, and the structural works must comply with Building Regulations (Part B for fire safety, Part F for ventilation). You must also notify your local housing authority and apply to amend your HMO licence to reflect the new room count and layout. Do not partition rooms and let them without prior licensing and planning approval.