Why business owners struggle with property numbers
You can read a P&L statement. You understand margins, cash flow, and ROI in a business context. But when someone starts talking about property yields, cap rates, and loan-to-value ratios, it can feel like a different language.
It is not. The concepts are almost identical to the ones you already use in your business. They just have different names. Let me translate.
Gross yield: Your top-line return
Gross yield is the simplest calculation in property. It is the annual rental income divided by the purchase price, expressed as a percentage.
Formula: (Annual Rent / Purchase Price) x 100
Example: You buy a house for 150,000 pounds. It rents for 750 pounds per month. That is 9,000 per year.
(9,000 / 150,000) x 100 = 6% gross yield
In business terms, think of this like revenue as a percentage of investment. It tells you the broad picture but not the whole story.
What to aim for: In the north of England, I look for 7-10% gross yield minimum. In the south, 5-6% is more typical because property prices are higher relative to rents. Below 6% in the north and I move on.
Net yield: Your actual return
Net yield is where reality kicks in. It is the annual rental income minus all operating costs, divided by the purchase price.
Formula: ((Annual Rent - Annual Costs) / Purchase Price) x 100
Your annual costs include:
- Mortgage interest payments
- Property management fees (typically 8-12% of rent)
- Maintenance and repairs (budget 10% of rent)
- Insurance (landlord policy, roughly 200-400 per year)
- Void periods (assume 1 month per year with no tenant)
- Ground rent and service charges (for leasehold properties)
Example using the same property:
- Annual rent: 9,000
- Mortgage interest (75% LTV at 5%): 5,625
- Management (10%): 900
- Maintenance (10%): 900
- Insurance: 300
- Void (1 month): 750
- Total costs: 8,475
Net income: 9,000 - 8,475 = 525
(525 / 150,000) x 100 = 0.35% net yield
That looks terrible. But wait. This is not the right way to measure it, because you did not actually invest 150,000 of your own money. That is where cash-on-cash return comes in.
Cash-on-cash return: The number that actually matters
Cash-on-cash return measures the annual profit against the cash you actually invested. Not the property price. The money that came out of your pocket.
Formula: (Annual Net Profit / Total Cash Invested) x 100
Your total cash invested includes:
- Deposit (25% for buy-to-let: 37,500)
- Stamp duty (at 150k with surcharge: roughly 5,500)
- Legal fees: 1,500
- Survey: 500
- Refurbishment: 5,000 (if needed)
- Total cash in: 50,000
Using the net income from above: 525 per year.
(525 / 50,000) x 100 = 1.05% cash-on-cash return
Still not great. This tells you the deal needs work. Either the rent is too low, the price is too high, or the costs are too heavy.
Making the numbers work
Let me show you the same area but a better deal:
- Purchase price: 120,000 (you found something below market value)
- Monthly rent: 725 (strong local demand)
- Annual rent: 8,700
- Mortgage interest (75% LTV at 5%): 4,500
- Management: 870
- Maintenance: 870
- Insurance: 300
- Void: 725
- Total costs: 7,265
- Net income: 1,435
Cash invested:
- Deposit: 30,000
- Stamp duty: 4,100
- Legal and survey: 2,000
- Light refurb: 3,000
- Total: 39,100
(1,435 / 39,100) x 100 = 3.67% cash-on-cash return
Better. And this does not account for capital appreciation. If the property goes up 3% in value, that is another 3,600 pounds of equity growth on top.
The numbers business owners forget
Coming from a business background, there are a few things that trip people up:
Mortgage interest, not repayment. For investment property analysis, you look at the interest portion only. The capital repayment is not a cost. It is you paying down debt and building equity. Think of it like paying off a business loan.
Void periods are real. Do not calculate based on 12 months of rent. Budget for at least one month empty per year. If you have a great tenant who stays for years, that is a bonus, not the baseline assumption.
Maintenance is not optional. Boilers break. Roofs leak. Kitchens need updating. Budget for it upfront rather than being surprised.
Tax changes everything. Since 2020, mortgage interest relief for individual landlords has been restricted. You can only claim a 20% tax credit on mortgage interest, not deduct it from rental income. This matters a lot at higher rate tax. Speak to an accountant about whether to buy personally or through a limited company.
The quick screening test
When I source deals at Red Cardinal, I use a quick screening calculation before doing the full analysis:
- Monthly rent x 12 = annual rent
- Divide by asking price
- If it is below 7%, skip it
- If it is above 7%, do the full numbers
This saves hours of detailed analysis on properties that were never going to work.
Comparing to other investments
A savings account gives you 4-5% right now with zero effort. So why bother with property?
Because of the mortgage multiplier. You are getting a return on an asset worth 4x what you invested. A 3% capital appreciation on a 150k property is 4,500. On your 37,500 deposit, that is a 12% return on your cash, on top of the rental yield.
Property is work. It requires knowledge, management, and capital. But for business owners who want to build long-term wealth with an asset they can understand and control, the numbers make sense if you pick the right deals.
Next steps
Get a spreadsheet together. Model three or four real properties from Rightmove using these calculations. See what the numbers look like in your target area. That exercise alone will teach you more about property investment than any course.
Join the builders
Weekly insights on AI, automation, and building businesses that scale.
Keep Reading