semi commercial mortgage calculator
This calculator estimates the maximum loan and monthly payment on a UK semi-commercial or mixed-use mortgage. It models the interest coverage ratio (ICR) stress test against the combined gross rent from both the residential and commercial elements, then applies the blended LTV cap. The lower of the two determines the maximum loan.
FD Commercial arranges semi-commercial mortgages from £250,000 across England, Scotland and Wales.
What this calculator models
ICR stress test on combined gross rent at 125% for limited company ownership or 140% for personal ownership. Notional rate of 8% for variable products, or the actual fixed rate if selecting a fixed term. Blended LTV cap applied to total property value. Maximum loan is the lower of the ICR-calculated figure and the LTV cap. Monthly payment shown on interest-only or capital and interest basis. The constraint indicator shows whether rental income or LTV is the limiting factor.
Minimum loan: £250,000.
UK Semi-Commercial Mortgage Calculator
Results update automatically. All figures are indicative estimates.
Indicative estimates only. ICR test applied to gross rent with no deductions for voids, management or maintenance. Lender appetite on semi-commercial varies significantly by asset type and commercial tenant. Figures do not constitute a mortgage offer. Speak to FD Commercial for accurate indicative terms.
How the ICR stress test works on semi-commercial
Lenders do not simply look at the rent a property generates. They test whether that rent, at a stressed interest rate, covers the mortgage payment by a sufficient margin. This is the interest coverage ratio test. For semi-commercial mortgages, the test is applied to the combined gross rent from both the residential and commercial elements.
For limited company borrowers, most lenders require the annual gross rent to cover the notional interest cost at 125%. For personal borrowers, the cover requirement rises to 140%. The notional rate is typically 8% regardless of the actual rate on offer, or the actual fixed rate if borrowing on a five-year or longer fixed term with some lenders.
The formula is: maximum loan = annual gross rent divided by (ICR multiplied by notional rate). With £50,000 annual rent, a 125% ICR and an 8% notional rate, the income-supported loan is £500,000. If the LTV cap on a £500,000 property at 75% is £375,000, the LTV cap becomes the binding constraint and the maximum loan is £375,000.
Example: shop with flat above, Bristol
Residential rent: £1,500/month. Commercial rent: £2,667/month. Total: £4,167/month, £50,004/year. Property value: £500,000. LTV cap: 75% = £375,000. Ltd company, variable rate, 8% notional, ICR 125%.
Income-supported loan: £50,004 / (1.25 x 0.08) = £500,040. LTV cap: £375,000. Max loan: £375,000 (LTV-limited). Monthly IO payment: £375,000 x 8% / 12 = £2,500. Achieved rental cover: 1.67x (comfortably above the 1.25x requirement).
LTV on mixed-use property
Most lenders apply a blended LTV to the total property value rather than splitting the residential and commercial elements separately. The standard maximum for semi-commercial is 75% LTV, though this varies by lender and is influenced by the proportion of commercial income, the nature of the commercial tenant, the lease length remaining, and whether the commercial element is let or vacant.
A property where the commercial element is vacant, or where the commercial tenant is on a short lease, will typically attract a lower maximum LTV than one with a long-term commercial tenant in occupation. Properties where the commercial income represents the majority of total rent may be assessed more conservatively than those where residential income dominates.
Lender appetite on semi-commercial is narrower than on standard buy-to-let. Not all commercial lenders offer semi-commercial products, and the ones that do apply widely varying criteria. Using a broker with direct access to the semi-commercial market is the most efficient way to identify the right lender for your specific asset.
According to the Valuation Office Agency 2023 Non-Domestic Rating data, there are approximately 2.1 million rateable properties in England and Wales. Retail premises, which form the commercial component of the majority of semi-commercial investments, account for approximately 520,000 of these, making semi-commercial mortgage finance one of the most broadly applicable commercial lending products in the UK market.
Source: Valuation Office Agency, Non-Domestic Rating Statistics (gov.uk)The Bank of England base rate stood at 3.75% in April 2026, down from the 5.25% peak reached in August 2023. Semi-commercial mortgage lenders calculate the ICR stress test using a notional rate of 8% for variable products, approximately 425 basis points above the current base rate. This gap between the pay rate and the stress test rate is why many semi-commercial loans are income-constrained rather than LTV-constrained at current values.
Source: Bank of England, Monetary Policy Committee decisionsAlso on mobile
Use this calculator and 3 more inside the FD Commercial app
Free on Google Play. No signup, no in-app purchases. Includes the Bridging Cost Analyser, Development Appraisal, BTL Stress Tester, and a Stamp Duty Calculator covering SDLT, LBTT and LTT.
Semi-commercial lending depends heavily on the specific property and tenant mix. We have direct access to lenders who specialise in this space and can identify appetite before you commit to a purchase.
Call 03300 100315Frequently asked questions
How does the ICR stress test work on a semi-commercial mortgage?
The ICR test measures whether the combined gross rent from both the residential and commercial elements covers the notional interest cost by the required multiple. For limited company borrowers, lenders require 1.25x cover at a notional rate of 8% for variable products. For personal name borrowers, the requirement is 1.40x. The formula is: maximum income-supported loan = annual gross rent divided by (ICR multiplied by notional rate). The final loan is the lower of this figure and the LTV cap.
What is a typical LTV on a semi-commercial mortgage?
The standard maximum LTV on semi-commercial mortgages is 75%, applied to the total blended value of the property. Some lenders will go to 80% where the residential component is strong and the commercial tenant is on a long lease with a creditworthy covenant. Properties where the commercial element is vacant, or on a short lease, typically attract lower LTV limits, often 65% to 70%.
What is the difference between a semi-commercial and commercial mortgage?
A semi-commercial mortgage (also called a mixed-use mortgage) is used for properties that contain both residential and commercial elements, such as a shop with a flat above or an office building with a residential unit. A commercial mortgage is used for entirely commercial property. Semi-commercial products are available from both specialist commercial lenders and some mainstream lenders, but the market is narrower than for either pure residential or pure commercial property.
Can I get a semi-commercial mortgage through a limited company?
Yes, and limited company ownership is common for semi-commercial investment properties. The ICR test for limited company borrowers uses a lower multiplier of 1.25x rather than the 1.40x required for personal name borrowers, which generally produces a higher maximum loan for the same income. Lenders will assess the company's purpose (typically an SPV), directors' guarantees, and the overall structure.
What happens if the commercial element is vacant?
If the commercial element is vacant, lenders will typically exclude that element from the ICR calculation entirely and advance only against the residential income, with a reduced LTV. Some lenders will consider a vacant commercial unit but will apply a conservative stressed rental figure rather than the passing rent. Vacancy in the commercial element significantly reduces the income-supported loan and may also reduce the LTV the lender is willing to offer.
What is the minimum semi-commercial mortgage at FD Commercial?
The minimum loan is £250,000. FD Commercial arranges semi-commercial mortgages across England, Scotland and Wales for investors and owner-occupiers. We have direct access to specialist lenders in this space and do not charge a broker fee on most transactions.
Your property may be repossessed if you do not keep up repayments on a mortgage or other loan secured against it. Rates and calculator results are indicative only and subject to individual lender assessment, underwriting, and commercial tenant review. Results do not constitute a mortgage offer or lending commitment. FD Commercial arranges finance across England, Scotland and Wales. Minimum loan £250,000.