Ltd Company Mortgage Calculator (UK Buy-to-Let)
Estimate your monthly payment, LTV, rental stress test, and cash flow for a property purchased through a limited company/SPV.
How this ltd company mortgage calculator helps
If you are buying a buy-to-let property through a limited company (often an SPV), your deal usually gets assessed differently from a personal buy-to-let mortgage. This ltd company mortgage calculator gives you a fast way to check the numbers before you apply.
In one view, you can estimate:
- Loan amount and loan-to-value (LTV)
- Monthly mortgage payment (interest-only or repayment)
- Minimum rent required by an Interest Coverage Ratio (ICR) stress test
- Simple monthly and annual cash flow before maintenance, voids, insurance, and management costs
What is a limited company mortgage?
A limited company mortgage is a loan made to a company rather than to you as an individual. In UK property investing, this is often an SPV (Special Purpose Vehicle) created specifically to hold rental properties.
Why investors use a company structure
- Potential tax planning advantages depending on profit level and extraction strategy
- Potentially easier to retain profits inside the company for future purchases
- Clean separation between personal and property business finances
That said, rates, arrangement fees, legal costs, and accounting complexity can differ from personal ownership. Always compare full costs, not just one headline rate.
Key figures to understand before applying
1) LTV (Loan-to-Value)
LTV tells you how much you are borrowing versus property value. Example: borrow £187,500 on a £250,000 property, and your LTV is 75%.
2) Interest-only vs repayment
- Interest-only: lower monthly payments, but capital remains outstanding at term end.
- Repayment: higher monthly payments, but the mortgage balance amortises to zero over the term.
3) ICR (Interest Coverage Ratio)
ICR is a lender stress test. It compares rent against stressed monthly interest. A common requirement is 125% (sometimes higher depending on lender and borrower profile).
4) Stress rate
Lenders may test affordability at a notional rate above your actual pay rate. That is why a deal can look fine on real payments but still fail underwriting.
Calculator assumptions and formula logic
This calculator uses standard mortgage math:
- Loan amount = Property value − Deposit
- Interest-only payment = Loan × (Rate ÷ 12)
- Repayment payment = amortisation formula using rate and term
- Required rent (ICR) = Stressed monthly interest × ICR%
It also shows gross yield and basic cash flow for quick screening. This is useful at shortlist stage when you are deciding whether to pursue a viewing, valuation, or full application.
How to use this ltd company mortgage calculator in practice
Step-by-step workflow
- Enter purchase price and deposit.
- Set your expected mortgage rate and term.
- Choose interest-only or repayment.
- Input projected monthly rent from local comparables.
- Set ICR and stress rate to match target lender criteria.
- Review the pass/fail output and adjust assumptions.
As a rule, run three scenarios: conservative, realistic, and optimistic. This quickly shows whether your margin is robust or too thin.
Common mistakes investors make
- Ignoring lender stress testing and focusing only on pay rate
- Underestimating total purchase and setup costs
- Forgetting letting fees, maintenance reserves, and void periods
- Assuming all lenders apply the same ICR and stress methodology
- Not checking EPC, licensing, and local rental demand before committing
Should you buy through a company or personally?
There is no universal answer. The right structure depends on income level, profit extraction plans, number of properties, financing strategy, and long-term goals. A landlord with one property may prefer simplicity; a portfolio investor may value retained-profit flexibility.
Before making structural decisions, compare:
- Mortgage product choice and pricing
- Company setup and ongoing accounting costs
- Tax impact under your specific circumstances
- Exit strategy (refinance, hold, or sell)
Final thoughts
A good ltd company mortgage calculator should do more than show one monthly payment. It should help you understand whether your rent supports the financing under real underwriting conditions. Use this page to screen deals quickly, then validate with a broker and accountant before committing funds.
Important: This tool is for educational planning only and does not constitute mortgage, tax, legal, or investment advice.