HMO Investment
HMO yields in Cardiff
How to calculate gross and net yield on a Cardiff HMO, which costs to include, what the numbers look like across the city's main areas, and how to use yield to set a sensible maximum purchase price.
Cardiff's HMO market consistently delivers yields well above the city's single-let average, but the headline figures that appear in property listings rarely tell the full story. A gross yield of 10 per cent and a net yield of 6 per cent can describe the same property; knowing which number you are looking at, and how to move between the two, is the starting point for any credible deal appraisal in Cardiff or Wales more broadly.
This guide explains how to calculate both gross and net yield, what costs to include in a realistic net figure, how Cardiff HMO yields compare to single-let returns, and how to work backwards from a target yield to establish a maximum purchase price before you make an offer.
Gross yield: the quick screen
Gross yield expresses annual rental income as a percentage of the purchase price, before any costs are deducted. The formula is straightforward: divide annual gross rent by the purchase price, then multiply by 100. For a Cardiff five-bed HMO generating £600 per room per month, that is £3,000 a month or £36,000 a year. Against a purchase price of £300,000, the gross yield is 12 per cent. Against £360,000, it falls to 10 per cent.
The simplicity of gross yield is its main purpose: it answers the question "does this deal merit further attention?" quickly, without requiring detailed cost assumptions. Property portals and investor networks tend to quote gross figures, so it is the common language of initial deal filtering. What gross yield cannot tell you is what you will actually keep after the costs of running the property are accounted for.
Net yield: what you actually retain
Net yield adjusts the income figure for all the operating costs of the property and expresses what remains as a percentage of the purchase price. The gap between gross and net yield on a Cardiff HMO typically runs from three to five percentage points, depending on cost structure, management approach and whether the loan is interest-only or repayment. A realistic appraisal should include every line below.
| Cost item | Indicative annual range | Notes |
|---|---|---|
| Mortgage interest | £7,000 to £14,000 | Depends on loan amount and rate. Interest only only; do not include capital repayment in yield maths. |
| Management fees (if agent) | £2,400 to £4,320 | 8 to 12 per cent of gross rent. See our HMO management guide. |
| Maintenance and repairs | £1,500 to £3,600 | Older Cardiff terraces typically need 8 to 10 per cent of gross rent set aside. |
| Buildings and landlord insurance | £600 to £1,200 | HMO policies are priced higher than standard buy-to-let. Always declare the HMO use. |
| Gas safety certificate | £80 to £150 | Required annually. Engineer should be Gas Safe registered. |
| EICR | £250 to £500 (every 5 years) | Amortised, roughly £50 to £100 per year. |
| HMO licence fee | £200 to £600 (every 5 years) | Cardiff Council sets fees; amortised gives £40 to £120 per year. |
| Void allowance | £1,500 to £3,600 | Typically 4 to 8 weeks per room per year in a 5-bed; varies sharply by area and season. |
HMO yields versus single-let in Cardiff
The yield advantage of HMOs over single-let properties in Cardiff is structural. Multiple contract-holders each paying room-by-room rent generate considerably more total income from the same building than a single household on a whole-house tenancy. A Cardiff terrace that might achieve £1,100 to £1,300 a month as a single-let can realistically generate £2,800 to £3,500 a month as a five or six-bed HMO in Cathays or Roath.
At a £300,000 purchase price, that single-let income produces a gross yield of roughly 4.8 per cent, while the HMO income puts the same property at 11 to 14 per cent gross. The gap narrows once you factor in the higher management complexity, more demanding compliance obligations under Welsh law, and greater upfront refurbishment cost, but the net advantage of a well-run Cardiff HMO over a comparable single-let remains significant. For a deeper look at HMO investment strategy in Cardiff, including a worked deal appraisal, see our 2026 strategy guide.
Key takeaways
What Cardiff HMO yield figures to aim for
- Gross yield of 10 to 14 per cent is achievable in Cardiff's core HMO areas (Cathays, Roath, Heath).
- Net yield of 6 to 8 per cent is a realistic target after operating costs on a deal bought at a sensible price.
- Net yield below 5 per cent warrants close scrutiny of purchase price, cost assumptions or both.
- Room rents in Cathays and Roath currently run from around £500 to £650 per month inclusive of bills, depending on room size and spec.
- Void periods and maintenance are the two most frequently underestimated cost items in an HMO appraisal.
- Work backwards from a target yield to set your maximum purchase price, not the other way around.
What drives yield in a Cardiff HMO
Location is the most significant factor. HMOs close to Cardiff University and Cardiff Metropolitan University draw the strongest student demand, which supports higher room rents and shorter void periods. Cathays and Roath in particular have established demand that refills rooms quickly in the summer letting window ahead of the September academic year. Areas further from campus can still work well for professional HMOs, but the letting cycle is less concentrated and demand is harder to predict season to season.
Room size and specification also matter more than many investors initially expect. A room of 12 square metres with an en suite commands meaningfully higher rent than an 8-square-metre room with shared facilities. Investing in en suites and reasonable room sizes during refurbishment costs more at entry, but improves both rental income and re-letting speed, particularly for professional tenants who may compare your rooms against purpose-built alternatives. For an understanding of what a full refurbishment involves, see our HMO refurbishment costs guide.
Working backwards from a target yield
Of all the variables in a yield calculation, purchase price is the one most directly under your control during a negotiation. If a five-bed Cardiff HMO generates £3,000 a month in gross rent and your target gross yield is 11 per cent, your maximum purchase price is approximately £327,000. Paying £360,000 drops the gross yield to 10 per cent; paying £400,000 takes it below 9 per cent. That same arithmetic, applied to your realistic net income after costs, tells you how much the deal actually earns per pound invested once it is running.
Experienced investors set their target yield, calculate the income supported by the property, and derive the maximum price from that — rather than accepting the vendor's asking price and calculating yield as a by-product. In a Cardiff market where property values in Cathays and Roath remain competitive, the discipline of a maximum price ceiling is what separates good deals from well-publicised ones. For current context on Cardiff HMO market conditions including room rents and area-by-area demand, see our 2026 market update.
Appraise your deal
HMO gross and net yield calculator
Enter your purchase price, rental income and estimated annual costs to see gross and net yield side by side. Figures are illustrative and not financial advice.
Include mortgage interest, agent fees, maintenance, insurance, licensing and a void allowance.
Illustrative only. Assumes full occupancy. Actual returns depend on finance costs, voids, maintenance and market rents. Not financial advice.
Common questions
Cardiff HMO yield FAQs
What is a realistic net yield for a Cardiff HMO?
A net yield of 6 to 8 per cent is achievable on a well-located Cardiff HMO bought at a sensible price. Properties in core student areas like Cathays and Roath tend to sit at the higher end of that range because strong occupancy limits void costs. Yields below 5 per cent net warrant close scrutiny of the purchase price, the cost assumptions, or both. Always build your appraisal on realistic costs rather than best-case income.
Should I use gross or net yield when comparing Cardiff HMOs?
Use gross yield as a quick first screen to filter out deals that are clearly unviable. Once a property clears your gross yield threshold, switch to net yield for the serious appraisal. Comparing properties on gross yield alone is misleading if the cost profiles differ significantly, for example if one has higher management fees, a larger licensing obligation, or more deferred maintenance than the other.
What costs should I include in a Cardiff HMO net yield calculation?
A thorough net yield calculation should include mortgage interest (not capital repayment), building and landlord contents insurance, an agent management fee if applicable, a maintenance and repair allowance (typically 8 to 12 per cent of gross rent for an older Cardiff property), HMO licensing fees amortised over the licence period, gas safety and EICR renewal costs, and a void allowance. Omitting any of these inflates the net yield and makes the deal look stronger than it is.
How does the purchase price affect yield on a Cardiff HMO?
The purchase price is the single biggest lever in a yield calculation. A Cardiff HMO generating £36,000 a year in gross rent delivers a gross yield of 12 per cent at £300,000, 10 per cent at £360,000, and just under 9 per cent at £400,000. Experienced investors work backwards from a target yield to establish a maximum purchase price rather than accepting the vendor's asking price as the starting point.
Do Cardiff HMO yields vary by area?
Yes, meaningfully. Cathays and Roath command the strongest gross yields because high student demand supports consistently high room rents relative to purchase prices. Areas further from the university, such as Canton or Pontcanna, tend to attract lower gross yields partly because purchase prices are higher and partly because room rents do not rise at the same rate. Professional HMOs in those areas can still deliver competitive net yields if the cost structure is tight.
Sources & method
Yield calculations and cost ranges in this article are based on Arthur & Hamilton's experience managing HMOs in Cardiff and are illustrative. Room rents reflect typical Cardiff HMO market rates as of mid-2026; rents vary by area, room size and specification. Licensing fee ranges are based on Cardiff Council's published schedules, which change periodically. For authoritative guidance on landlord obligations in Wales, see Rent Smart Wales and the Welsh Government's renting homes guidance. This article is general information only, not financial or legal advice. Seek qualified professional advice before making any investment decision. Last updated 15 July 2026.
Cardiff HMO investment
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