BTL portfolio metrics.

Property portfolio calculator measures aggregated value, equity, income, and yield across multiple properties. 5 properties × 400k = 2M portfolio value. 1.5M total mortgages = 500k equity. 40k annual income = 8% yield on equity. Useful for portfolio landlords managing multiple BTL holdings.

Example: 5-property portfolio. Average value 400k = 2,000,000 total. Total loans 1,500,000. Equity = 500k. Average annual net income per property 8k = 40,000 total annual income. Portfolio yield (on equity) = 8%. LTV = 75% across portfolio. Healthy leveraged portfolio with reasonable cash flow.

Portfolio landlord considerations 4+ properties): (1) Stricter mortgage rules (full portfolio stress test). (2) Limited company SPV structures common (better Section 24 treatment). (3) Diversification benefits (location, property type, tenant mix). (4) Portfolio-level reporting and management. (5) Refinancing optimisation across the portfolio. Most successful BTL investors hold 5-20 properties - enough for diversification but manageable. Above 20: typically need professional property management or transition to commercial real estate.

A worked example

Try the defaults: number of properties of 5, average property value of 400,000, average annual net income per property of 8,000, total loan balance across portfolio of 1,500,000. The tool returns 2,000,000.00. You can adjust any input and the result updates as you type — no submit button, no reload. That's the real power here: seeing how sensitive the output is to one or two assumptions.

What moves the number most

The result responds to Number of Properties, Average Property Value, Average Annual Net Income per Property, and Total Loan Balance Across Portfolio. The rate and the time horizon usually dominate — compounding means a small change in either reshapes the final figure more than a similar shift in contribution size. Test this by doubling one input at a time.

The formula behind this

Portfolio value = properties × avg value. Equity = value - loans. Yield = income / equity. Everything the calculator does is shown in the formula box below, so you can check the math against your own spreadsheet if you want.

Where this fits in planning

This is a "what-if" tool, not a forecast. Use it to test ideas before committing: what happens if the rate is 2% lower than hoped, what happens if you add five more years. The value is in the scenarios you run, not the single answer you get from the defaults.

What this doesn't capture

Steady-rate math ignores real-world volatility. Actual returns are lumpy; sequence-of-returns risk matters most in drawdown; fees and taxes drag on compound growth; and behaviour changes in drawdowns can reduce outcomes below the projection. Treat the number as one scenario, not a forecast.