Cap Rate Calculator
Calculate the capitalisation rate of a property to evaluate rental yield and investment returns.
What this calculator does
The capitalisation rate — net yield, in UK terms — is the return a property produces before any consideration of how it is financed. Enter the property value, its net operating income, and the monthly rent, and the calculator returns the yield, the value implied at a range of yields, and the gross rent multiplier as a secondary check.
The relationship works in both directions. Given a price you get a yield; given a yield you get a value. The second direction is how investment property is valued in practice, which is why the implied value table matters as much as the headline percentage: it shows what the same income is worth to buyers who require different returns.
When to use it
Use it to compare properties that differ in price, type, and financing — a £250,000 terrace and a £900,000 block of flats can be ranked on the same scale precisely because the mortgage is excluded.
It is also the right tool for challenging an asking price. If comparable investments in the area change hands on a 6.5 percent net yield and the asking price implies 5.4 percent, you have a defensible figure to negotiate with rather than an opinion. And it prices refurbishment work: at a six percent yield, every £1,000 of annual net income added through a rent increase or a cost saving is worth roughly £16,700 of capital value.
Understanding the inputs
Property value is the asking or valued price when you want a yield, and can be set aside when you are working backwards from income and a market yield. Net operating income is the input that determines whether the answer means anything: it must be annual rent after a void allowance, less every running cost, and it must exclude mortgage interest, capital works, and your tax.
Include letting agent fees at local rates even if you self-manage, include the full service charge and ground rent on a leasehold property, and include a maintenance provision. Omitting those is how advertised yields end up a point or two above reality. Monthly rent drives the gross rent multiplier, which is a rougher screen that ignores costs entirely.
How is this calculated?
Cap Rate = (Net Operating Income / Property Value) × 100. NOI = Annual Rent − Operating Expenses.
A worked example
Take a small block of flats on the market at £700,000 producing £42,000 of net operating income after management, insurance, maintenance, and a void allowance. The yield is £42,000 divided by £700,000, or 6.0 percent. Gross rents of £4,200 a month give £50,400 a year, so the gross rent multiplier is about 13.9.
Run it the other way and the negotiating position appears. If comparable blocks locally trade on a 6.5 percent net yield, the same £42,000 implies a value of about £646,000 — roughly £54,000 under the asking price. Conversely, lifting net income to £46,000 by bringing two under-let flats to market rent raises the value at 6.5 percent to about £708,000, which is where refurbishment budgets earn their keep.
Limitations and assumptions
The yield is only as reliable as the income behind it, and net operating income is the figure most often flattered in marketing particulars. Full occupancy, no management fee, no maintenance provision, and an out-of-date service charge can each shift the result by half a point or more.
It is also a single-year snapshot. It says nothing about rent growth, tenant quality, lease length, deferred repairs, EPC upgrade costs, or what happens when an interest-only facility matures and needs refinancing at whatever rates then exist. Nor does it reflect tax — Section 24 means a leveraged higher-rate landlord's after-tax return can be far below the yield shown. Use this to screen and to price, then build a full cash flow model before committing.
Common Questions
- Is cap rate the same as rental yield?
- Close, but not identical. Cap rate uses net operating income after all running costs, which matches what UK investors call net yield. Gross yield uses rent before costs and is the figure most commonly quoted in property adverts, which is why advertised yields always look better than the return you actually receive.
- What is a typical yield in the UK?
- Net yields of five to seven percent are achievable in the North West, North East, Wales, and parts of the Midlands. In London and the South East, net yields of three to four percent are common because capital values have historically been driven by growth expectations rather than income.
- What counts as an operating cost?
- Letting agent fees, buildings insurance, ground rent and service charge on leasehold, repairs and maintenance, safety certificates, and an allowance for voids. Not included: mortgage interest, capital improvements, or your income tax. Excluding finance costs is deliberate — it lets you compare properties regardless of how each buyer funds the purchase.
- How do interest rates move yields?
- Upward pressure on rates pushes required yields up and capital values down, since no investor buys at a four percent yield when borrowing costs five and a half. That repricing has been visible across UK commercial property and increasingly in buy-to-let, where lender stress tests have quietly become the binding constraint on price.
- What does the implied value figure mean?
- It divides net operating income by a chosen yield to show what the property is worth to a buyer requiring that return. If comparable investments in the area change hands on a 6.5 percent net yield and your property produces £42,000, it is worth about £646,000 to that buyer whatever the asking price says.
- Can I increase value by cutting costs?
- Yes, and it is the mechanism behind commercial value-add work. Because value equals income divided by yield, at a six percent yield every £1 of annual cost removed adds about £16.67 of value. Renegotiating a £6,000 service contract to £4,000 creates roughly £33,000 of value.
- Does this work for residential buy-to-let?
- As an income screen, yes. As a valuation method, less so — UK houses and flats are valued by comparable sales, not by yield, so a strong yield does not mean a buyer will pay more. Yield-based valuation applies properly to blocks, HMOs, and commercial property.
- Should I trust an agent's quoted yield?
- Rarely without checking. Marketing particulars usually quote gross yield with no void allowance, no management fee, and no maintenance provision. Rebuild it from the actual service charge, a real insurance quote, and agent fees at local rates. Recalculated net yields commonly come out one to two points below the advertised gross.
- What about leasehold and service charges?
- They can dominate the numbers on a flat. Service charges of £2,000 to £3,000 a year plus ground rent are ordinary, and major works levies for roofs or cladding can arrive as five-figure demands. A lease under about 80 years also carries an expensive extension cost. All of it belongs in net operating income.
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