Lenders commonly lend around 60% to 75% of the property’s value. They also check that the rent, or the business’s profit if you occupy it, covers the interest with room to spare, often somewhere between 125% and 200% depending on the lender and the rate. Whichever test gives the lower figure usually sets the loan. The interest cover test in the calculator shows how your figures compare.

Commonly 25% to 40% of the price. On top of that come stamp duty at non-residential rates, legal and valuation fees and the lender’s arrangement fee. The Cash needed figure in the calculator adds these up for you.

You replace your current loan with a new one, often when a fixed or discounted rate ends or to release money from the property. The new lender values the property again and re-tests the loan-to-value and interest cover, so a lower valuation or a higher rate can change how much you can borrow. Costs commonly include valuation, legal and arrangement fees, and early repayment charges on the old loan if you leave early. To see the figures, enter today’s value as the price and the new loan you want.

Buy-to-let mortgages are for homes let to tenants. Commercial mortgages are for shops, offices, industrial units and mixed-use (semi-commercial) buildings, and some lenders use them for larger HMOs or portfolios. Commercial loans are usually priced case by case, often with a lower loan-to-value, and terms are commonly up to 25 years. Most are not regulated by the FCA, so many investors use an FCA-authorised commercial finance broker.

No. The calculator is an illustration of how commercial loans are commonly worked out, so you can understand the numbers. Real terms come from a lender or an FCA-authorised commercial finance broker.