The yield figure most Buy to Let investors quote is usually the least useful one

Gross yield is the number that gets quoted. It's the figure in the deal summary, the metric on the sourcing platform, the number shared between investors comparing notes. It's also, in isolation, the least useful figure in Buy to Let analysis — because it tells you what you could earn before every cost that actually matters has been taken out.

This isn't a technicality. The gap between gross and net yield on a Buy to Let deal is where the quality of the investment actually lives. Two deals with identical gross yields can have dramatically different net yields depending on their cost structures, management arrangements, and running costs. Understanding that gap — and knowing what drives it — is the difference between accurate analysis and a number that looks good on paper.

Why gross yield gets attention — and why it misleads

Gross yield is calculated simply: annual rent divided by purchase price, expressed as a percentage. It's easy to calculate, easy to compare, and universally understood. Those properties make it useful as a quick filter — a way to sort deals before doing any real analysis. The problem is that investors often stop there.

Gross yield strips out everything that costs money. It doesn't account for letting agent fees, which typically run between 8% and 15% of monthly rent for a managed service. It doesn't reflect void periods — the weeks or months when the property sits empty between tenants and no rent is coming in. It ignores maintenance and repair costs, which on an older property can be significant and unpredictable. It excludes landlord insurance, safety compliance costs, and any service charges or ground rent if the property is leasehold.

None of those costs are optional. They are the operating costs of a Buy to Let investment, and they arrive whether or not the gross yield number accounted for them. An investor who buys on gross yield and only discovers the true cost structure later isn't making a bad investment because they were unlucky — they're making a bad investment because they evaluated it on incomplete information.

The investors who make cleaner Buy to Let decisions are usually the ones who start with net yield — not as a refinement of the analysis — as the foundation of it.

What net yield actually tells you

Net yield takes the annual rent, subtracts all ongoing running costs, and divides the result by the purchase price. Done properly, this figure tells you what the investment actually produces — the return that lands in your account after the business of owning and managing the property has been paid for.

The most significant deductions in a typical Buy to Let calculation are: letting agent fees (if using a managed service), void allowance (a realistic estimate of the weeks per year the property sits empty — commonly modelled at 3–5% of annual rent), maintenance and repairs (typically estimated at 1–1.5% of property value annually for older stock), landlord insurance, and any leasehold running costs where applicable.

When you run these numbers against a typical Buy to Let deal, the gross-to-net gap is real and meaningful. A property showing 7% gross yield in a northern city might net 5% or less once management, voids, and ongoing costs are properly modelled. That's still a reasonable return for the right investor in the right location — a different decision than the 7% headline implies.

Same gross yield — very different investments

The most important thing net yield reveals is the difference between deals that look identical at the gross level. Consider two Buy to Let properties, both showing 7% gross yield. The first is a newer-build flat in a high-demand city centre location: low maintenance costs, strong tenant demand, minimal void risk, and a straightforward management arrangement. The second is an older terrace in a lower-demand area: higher maintenance liability, more frequent tenant turnover, and a management cost structure that reflects the additional work involved.

At the gross level, these are the same investment. At the net level, they're not even close. The newer flat might net 5.5–6%. The older terrace might net 4% or less once realistic void rates and maintenance allowances are applied. The investor who evaluates on gross yield alone cannot see this difference. The investor who models net yield can — and can make a properly informed comparison.

This also matters when comparing Buy to Let against other strategies. A Housing Association deal showing 5% gross yield looks worse than a 7% gross Buy to Let on the headline numbers. The Housing Association deal, however, has a compressed gross-to-net gap — management is handled by the housing provider, voids are effectively eliminated, and maintenance costs are reduced. The net yields of those two deals may be closer than the gross comparison suggests, and the management burden of the Housing Association arrangement is considerably lower. The same gross-to-net logic applies when evaluating HMO deals, where running costs and management intensity are structured very differently from single-let property.

Building a complete picture — beyond yield

Net yield is the right foundation for analysis — it is still not the complete picture. A thorough Buy to Let evaluation also considers: the capital position required (purchase price plus acquisition costs plus any refurbishment), the expected capital growth trajectory of the location, the liquidity of the asset if circumstances change, and the total demand on the investor's time and attention.

Yield — even net yield — is a rate of return on an asset. It doesn't tell you whether the asset itself is likely to appreciate, hold value, or decline. It doesn't tell you how long it will take to find a buyer if you need to exit. And it doesn't tell you whether the ongoing management burden of the investment suits your life.

The investors who get the most from Buy to Let tend to be those who are clear on all of these dimensions before committing — not just on the yield figure. They know what they need the investment to do, they've modelled the cost structure honestly, and they've chosen a location and property type that aligns with their operational appetite. The analysis starts with net yield, it does not end there.