How Much Does an HMO Conversion Cost in London?
Real 2026 figures from completed London projects. A 3-bed HMO conversion typically costs £40,000–£65,000. Here's what drives the price, what compliance work is required, and what to expect.
Illustrative imageQuick Answer — 2026 London HMO Conversion Costs
3-bed HMO (shared)
£40,000–£60,000
Fire safety + basic fit-out
5-bed with en-suites
£75,000–£105,000
Full plumbing to rooms
6-bed+ large HMO
£90,000–£130,000+
Complex M&E + compliance
⚠️ Ballpark figures only. Actual costs depend on room count, en-suite specification, fire safety complexity, and property condition. A detailed estimate requires a site visit.
HMO Conversion Price Breakdown
London market rates for 2026, based on completed HMO projects. All figures exclude VAT. Second-fix materials are client-supplied unless otherwise agreed.
| HMO type | Low estimate | High estimate |
|---|---|---|
| 3-bed HMO (shared bathrooms) | £40,000 | £60,000 |
| 4-bed HMO (shared bathrooms) | £52,000 | £75,000 |
| 5-bed HMO with en-suites | £75,000 | £105,000 |
| 6-bed HMO with en-suites | £90,000 | £130,000 |
| Large HMO (7-10 beds) | £120,000 | £200,000 |
| Fire safety retrofit only | £8,000 | £25,000 |
Typically Included
- ✓Room partitioning / layout reconfigurations
- ✓Grade A interlinked fire alarm system (BS 5839)
- ✓Fire doors with intumescent strips and smoke seals
- ✓Emergency lighting on escape routes and stairs
- ✓Thumb-turn locks on all bedroom doors
- ✓Kitchen upgrades (commercial-grade worktops, additional hobs)
- ✓Communal bathroom/shower room fit-out
- ✓En-suite plumbing (where specified)
- ✓Rewiring and additional circuits per room
- ✓Building Regulations compliance sign-off
Standard Exclusions
- ✗HMO licence application and fees (your responsibility)
- ✗Second-fix materials (beds, wardrobes, white goods)
- ✗Carpet installation
- ✗Architect drawings (priced separately if required)
- ✗Planning permission (where Article 4 applies)
- ✗Structural engineer if existing structure is compromised
- ✗External works and landscaping
- ✗Boiler replacement if current system undersized
- ✗Insurance upgrades or landlord compliance certificates
What Drives HMO Conversion Costs
Number of bedrooms
More bedrooms means more fire doors, more circuits, more rooms to fit out. Each additional bedroom adds approximately £8,000–£15,000 to the project cost.
En-suites vs shared bathrooms
En-suites add approximately £5,000–£9,000 per room for plumbing, tiling, and fixtures. Properties with en-suites command higher rents but cost significantly more to convert.
Fire safety complexity
Fire safety is non-negotiable and non-negotiable. A 3-storey property requires more emergency lighting, a more complex alarm system, and may need a protected staircase — all adding cost.
Layout changes
Knocking walls, creating new rooms, or moving the kitchen dramatically increase cost. Starting with a well-proportioned house that converts efficiently saves significant money.
Property condition
A tired or poorly maintained property requires remedial work before HMO conversion work can begin — damp, old wiring, poor drainage. This is why a pre-conversion survey is essential.
Local authority requirements
Different London boroughs have different HMO standards. Some require minimum room sizes, specific fire suppression systems, or improved soundproofing. Check with your local authority.
The Investment Case for HMO Conversion in London
HMO properties in London consistently generate higher rental yields than single-let properties — often 7–12% gross versus 3–5% for a standard let. The higher build cost is typically recovered within 2–4 years through increased rental income.
7–12%
Typical HMO gross yield in London
3–5%
Typical single-let gross yield in London
2–4 yrs
Typical payback period on HMO conversion cost
Figures are illustrative. Actual yields depend on location, room specification, management costs, and void periods. Always take independent financial advice.
Get an HMO Conversion Estimate
Use the estimator for a rough budget range before booking a site visit.
Ballpark figures only. A detailed, itemised estimated quotation follows a site visit.
Quick Estimate
Adjust the options to get a quick ballpark — not a quote, but a useful starting point.
Want more detail? Try the full cost calculator →
Independently reviewed
Read what clients say — in full, with our replies — on Checkatrade and Google.
HMO Conversion FAQs
How much does an HMO conversion cost in London?+
Do I need planning permission for an HMO?+
What HMO licensing is required in London?+
What fire safety work is required for an HMO?+
Talk to us about your HMO conversion
Tell us about your property — current layout, target room count, borough. We'll advise on licensing requirements, scope, and arrange a site visit when you're ready.