ROI vs Yield vs Cash Flow: What Actually Matters in UK Property?
2026-07-18
"This property yields 8%." "My ROI is 12%." "I'm cashflow-positive on every property."
These statements might all be true and still describe a terrible investment — because each metric answers a different question, and none of them tells the whole story alone.
The investors who make consistently good decisions understand what each metric measures, when to use it, and what it hides. This guide clarifies all three.
The Three Metrics
Yield: How the Asset Performs
Gross Yield = Annual Rent / Property Value x 100
Yield measures the income return of the property as an asset, independent of how you financed it. A property worth £200,000 renting for £12,000/year yields 6% whether you paid cash or used a 90% mortgage.
What it's good for: Comparing properties, areas, and strategies on a like-for-like basis. It's the universal screening metric.
What it hides: Every cost. Yield tells you nothing about mortgage payments, management fees, maintenance, voids, or tax. A 7% gross yield property can lose money every month.
For the full breakdown of gross vs net yield, see How to Calculate Rental Yield UK.
Cash Flow: What Hits Your Bank Account
Monthly Cashflow = Monthly Rent - ALL Monthly Costs
Cashflow is the most practical metric. It's the actual money you receive (or pay out) each month after every expense: mortgage, management, maintenance, insurance, voids. Positive cashflow means the property puts money in your pocket. Negative cashflow means you're subsidising it.
What it's good for: Day-to-day financial planning. Can you sleep at night? Is the property self-sustaining? Will a rate rise or void period send you into the red?
What it hides: How much capital you deployed to generate that cashflow. £100/month cashflow is great if you invested £20,000. It's terrible if you invested £200,000.
ROI: Your Total Return
ROI = (Annual Cashflow + Equity Growth) / Total Cash Invested x 100
ROI (Return on Investment) is the most comprehensive metric. It captures both income and capital growth relative to what you actually put in.
Equity growth comes from two sources:
- Capital appreciation (the property goes up in value)
- Mortgage paydown (if on repayment, each month reduces the debt)
What it's good for: Assessing the total return on your deployed capital. This is the metric that answers "is my money working hard enough?"
What it hides: Timing and liquidity. A 15% ROI is meaningless if the capital appreciation is unrealised and you can't access it without selling.
How They Differ in Practice
Same property, same numbers — three very different stories:
Property: £200,000, renting at £1,000/month. 75% LTV mortgage at 5% (interest-only). Costs: management 10%, maintenance 10%, insurance £25/month, void 1 month/year.
Cash deployed: £50,000 deposit + £11,500 SDLT + £2,500 costs = £64,000
| Metric | Calculation | Result |
|---|---|---|
| Gross yield | £12,000 / £200,000 | 6.0% |
| Net yield | £8,150 / £211,500 | 3.85% |
| Monthly cashflow | £1,000 - £625 - £100 - £100 - £25 - £83 | £67/month |
| Annual cashflow | £67 x 12 | £804 |
| Cash-on-cash | £804 / £64,000 | 1.26% |
| ROI (with 3% growth) | (£804 + £6,000 growth) / £64,000 | 10.6% |
:::stats 6.0% | Gross Yield £67/mo | Monthly Cashflow 1.26% | Cash-on-Cash 10.6% | ROI (with growth) :::
Look at how different these numbers are. The estate agent quotes 6% yield. Your actual cashflow return is 1.26%. But including capital growth, the total ROI is 10.6%. Which number matters?
All of them, for different purposes.
When to Use Each Metric
| Metric | Use When | Don't Use When |
|---|---|---|
| Gross yield | Screening properties quickly, comparing areas | Making a buy/don't-buy decision |
| Net yield | Assessing the property's standalone income performance | Accounting for your leverage or financing |
| Monthly cashflow | Checking affordability, stress testing, budgeting | Evaluating long-term wealth building |
| Cash-on-cash | Measuring how hard your deployed capital works | Comparing unleveraged and leveraged properties |
| Total ROI | Evaluating the full investment return over time | Short-term decisions (growth is unpredictable) |
The Danger of Using Just One
Only Looking at Yield
"I bought a 9% yielder!" Great. But if the area has high voids, the maintenance costs are double the norm, and the mortgage rate is 5.5%, that 9% gross yield could easily produce negative cashflow. Yield is a screening tool, not a decision tool.
Only Looking at Cashflow
"I'm £200/month positive!" Good, but you put £80,000 in. That's a 3% cash-on-cash return. A savings account pays more with zero risk. The cashflow is acceptable, but your capital isn't working hard. You might be better off in a cheaper property with less cash deployed producing the same cashflow.
Only Looking at ROI
"My ROI is 15%!" Impressive, but £12,000 of that is unrealised capital growth that only exists if you sell. If you need cash for a new boiler next month and your monthly cashflow is -£50, the theoretical ROI doesn't help. You can't spend capital appreciation on a boiler.
The Balanced Approach
Experienced investors use all three in sequence:
Step 1: Screen on yield. Does the property clear your minimum gross yield threshold (typically 5-6% for BTL)? If not, move on without further analysis.
Step 2: Check cashflow. After ALL costs including mortgage stress-tested at +2%, is the property cashflow-positive? If not, it doesn't survive adversity and it's not a deal at that price.
Step 3: Calculate cash-on-cash. Is your deployed capital earning an acceptable return? Typically you want 4%+ in the current market. Below that, consider whether the capital is better deployed elsewhere.
Step 4: Estimate total ROI. With conservative growth assumptions (2-3% annually, not the 5-6% optimistic projections), does the total return justify the effort, risk, and illiquidity compared to alternatives (stocks, bonds, REITs)?
The Deal Analyser runs all four in one screen — yield, cashflow, cash-on-cash, and stress testing — so you get the complete picture on any deal in seconds.
:::tool deal-analyser Get All Four Metrics in One Click :::
How the Numbers Change Over Time
One of property's unique advantages: the metrics improve naturally over time.
Year 1: Rent £1,000/month, mortgage £625, cashflow £67/month, cash-on-cash 1.26%
Year 5 (3% annual rent growth, same mortgage): Rent £1,159/month, mortgage still £625, cashflow £226/month, cash-on-cash 4.24%
Year 10: Rent £1,344/month, cashflow £411/month, cash-on-cash 7.7%
The mortgage is a fixed (or slowly changing) cost while rent grows with inflation. Every year, the cashflow and cash-on-cash improve. A deal that looks marginal in year 1 can be excellent by year 5.
The Cashflow Projection tool models this trajectory over your intended hold period.
:::tool cashflow-projection See How Returns Improve Over Time :::
Summary
| Metric | Measures | Quick Benchmark (2026) |
|---|---|---|
| Gross yield | Property income vs value | 5-6% minimum |
| Net yield | Property income vs value after costs | 3.5-4.5% typical |
| Monthly cashflow | Actual £ in your pocket | Must be positive after stress test |
| Cash-on-cash | Return on YOUR capital | 4%+ target |
| Total ROI | Income + growth on your capital | 8-12% with modest growth |
- Yield screens. Cashflow protects. ROI builds wealth.
- Never make a buy decision on one metric alone
- Always stress-test cashflow at +2% above current rates
- Growth is a bonus, not a guarantee — cashflow pays the bills
- The same property tells a very different story depending on which number you look at
Stop quoting one number. Run all of them. Let the complete picture make the decision.
Calculations in this guide are for illustrative purposes and should not be treated as financial advice. Always seek professional advice before making investment decisions.