Skip to content
Abodewise

Buy To Let Mortgage Calculator

Use this buy-to-let mortgage calculator to estimate borrowing, payments, and rental yield. Enter the property value, deposit, rent and mortgage assumptions, then choose what you want to check.

Back to Mortgage Calculators
Buy-to-let warning
This is a guide only. Buy-to-let mortgages have extra rules, fees and risks. Always check lender criteria (including rent coverage tests) and consider taking advice.
What do you want to check?
Estimate a rent-based borrowing limit using a lender-style stress check.
Mortgage type
Interest-only pays just the interest each month. Repayment pays interest and the balance, so monthly payments are usually higher.
Lender stress check (optional)
Loan amount£175,000.00
LTV (loan-to-value)70.00%
Monthly payment£802.08
Max loan from rent£159,151.19
Required rent (for your loan)£1,374.48
This uses your rent, ICR and stress rate to estimate a rent-based borrowing limit. Lenders may also consider other factors (such as your income and credit history).
Share this buy-to-let scenario
Copy a link that keeps your current numbers, so you can come back later or send it to someone.
How this buy-to-let mortgage calculator works

This calculator helps you estimate buy-to-let figures using your property value, deposit, rent and mortgage assumptions.

  • Borrow from rent: estimates what loan might be supported by your rent using a lender-style stress check (ICR and stress rate).
  • Payments: estimates the monthly mortgage payment for interest-only or repayment.
  • Yield and cashflow: estimates gross/net yield and monthly cashflow using your rent and cost assumptions.

It’s a simplified model and does not include all fees, taxes, insurance, maintenance, or rate changes.

Example model
This box is a fixed sanity-check using the default example numbers. It does not change when you edit the calculator.
ModeHow much can I borrow (from rent)?
Mortgage typeInterest-only
Property value£250,000.00
Deposit£75,000.00
Monthly rent£1,250.00
Example outputs
Loan amount£175,000.00
LTV (loan-to-value)70.00%
Monthly payment£802.08
Max loan from rent£159,151.19
Required rent (for your loan)£1,374.48
Gross yield6.00%
Net yield2.15%
Monthly net cashflow£447.92
Buy-to-let warning

This is a guide only. Buy-to-let lending rules vary by lender, and your real costs depend on fees, tax, maintenance, voids and rates.

Before making decisions, check lender criteria and consider speaking to a qualified mortgage adviser.
How it works

This buy-to-let calculator can answer three different questions, depending on the mode you select:

  • Payments: estimate interest-only or repayment mortgage payments on your loan amount.
  • Borrow from rent: estimate a rent-based maximum loan using the stress rate and ICR assumptions you enter.
  • Yield & cashflow: estimate gross/net yield and a simple monthly net cashflow (before tax) based on costs you include.

Lenders’ exact stress tests vary. Use this to explore sensitivity rather than to predict a lender decision.

Rates and thresholds

Last verified: 05/03/2026. ICR/stress-rate criteria vary by lender and are not universal.

For buy-to-let, “rates and thresholds” are typically lender-specific criteria. In this calculator you control the key assumptions:

  • ICR (%): the rent coverage ratio you want to model.
  • Stress rate: the interest rate the rent coverage test is applied at (not necessarily your pay rate).
  • Mortgage type: interest-only vs repayment changes both payments and cashflow.
Worked examples

Worked examples (rounded):

Example 1 — Yield & cashflow view (interest-only)

  • Property value £250,000; deposit £75,000 → loan £175,000 (70% LTV)
  • Rent £1,250/month; interest-only at 5.50% → payment ≈ £802.08/month
  • Gross yield: 6.00%; net yield (with the included costs in this model): 2.15%
  • Monthly net cashflow (before tax): £447.92

Example 2 — Borrowing limited by rent (ICR + stress rate)

  • Using ICR 145% and stress rate 6.50%, the rent-based max loan is ≈ £159,151.19
  • Rent required to support a £175,000 loan at that stress test is ≈ £1,374.48/month

Example 3 — Repayment payments mode

  • £175,000 repayment mortgage at 5.50% over 25y → monthly ≈ £1,074.65
  • Total interest over the full term (constant-rate model): £147,395.93
Edge cases and exclusions
  • Tax is excluded: rental income tax and mortgage interest restriction rules are not modelled.
  • Real costs vary: insurance, repairs, safety certificates, and agent fees can change cashflow significantly.
  • Void periods: empty months reduce effective rent; include a void % if you want a conservative scenario.
  • Stress vs pay rate: lenders may stress at a different rate than the one you pay.
  • Portfolio landlords / SPVs: criteria can differ; this model does not branch by borrower type.
Assumptions
  • This is a simplified estimate. Buy-to-let lender criteria and stress tests vary.
  • The interest rate is assumed to stay the same (unless you change it).
  • “Borrow from rent” uses an interest-only style rent coverage test (ICR and stress rate).
  • “Yield and cashflow” results depend heavily on costs and do not include taxes.
Methodology

Loan amount is property value minus deposit. LTV is loan amount divided by property value.

Payments are estimated as interest-only (interest only) or using a standard repayment model (capital and interest).

Borrow from rent estimates a rent-based maximum loan using a stress rate and an ICR rule.

Yield and cashflow use your rent and cost assumptions to estimate gross yield, net yield and monthly cashflow.

What to do next
FAQ
What is the “borrow from rent” mode in the buy-to-let mortgage calculator?
It estimates a rent-based borrowing limit using a lender-style stress check based on ICR and a stress rate.
What does ICR mean on the buy-to-let mortgage calculator?
ICR is the interest coverage ratio: the rent must cover the stressed interest payment by a certain percentage (for example 145%).
Why does the buy-to-let calculator use a “stress rate” that can be higher than my actual rate?
Lenders often test affordability at a higher assumed rate to see if the rent still covers the mortgage. This tool lets you explore that impact.
How is deposit percentage shown for buy-to-let inputs on this page?
The calculator derives deposit percentage from your property value and deposit amount. It is shown as a helpful context figure for the loan-to-value calculation.
When should I use the “payments” view in the buy-to-let mortgage calculator?
Use it to estimate monthly payments for interest-only or repayment. It is separate from the rent-based borrowing limit view.
What does the “yield and cashflow” mode include in the buy-to-let calculator?
It estimates gross and net yield and a simplified monthly cashflow using rent and the cost inputs you provide. It is not a full landlord profit model.
Are income tax and mortgage interest relief rules included in the buy-to-let cashflow estimate?
No. The cashflow estimate is before tax and does not model complex tax rules. If you need tax guidance, speak to a qualified accountant or adviser.
How should I represent letting agent fees in this buy-to-let calculator?
You can use the management fee percentage in the yield view. If you have fixed annual costs, you can include them in the annual non-mortgage costs field.
What does the void allowance do in the buy-to-let calculation?
It reduces effective rent by the percentage you enter, to reflect time without tenants. This is a simplified approach, but it helps you stress test the numbers.
Does the buy-to-let mortgage calculator include repairs, insurance, and compliance costs by default?
Not by default. Add your best estimate in the annual non-mortgage costs field to include those kinds of expenses in the yield and cashflow view.
Why can the rent-based maximum loan be lower than the loan implied by my deposit and property value?
Because rent coverage can be the binding constraint. Even if you have a large deposit, lenders may cap borrowing if rent does not pass the stress test.
What is the main limitation of using a single interest rate for buy-to-let modelling?
Rates can change and lenders price deals based on many factors. A single rate is useful for exploration, but it is not a quote or an offer.
Is the buy-to-let mortgage calculator suitable for HMOs or holiday lets?
It is built for a typical residential buy-to-let scenario. HMOs and holiday lets often have different lending rules and cost structures, so treat results as a rough guide only.
How do I share my buy-to-let scenario with someone else?
Use the share link to keep your current inputs in the URL. It is convenient for comparison, but avoid entering any sensitive personal information.
Why is there a buy-to-let warning callout on the calculator page?
Buy-to-let involves risk and extra rules, and the numbers can change with fees, tax, voids and rates. The warning is a reminder that results are estimates only.
Related calculators
Mortgage Calculator
Calculate your monthly mortgage payments based on loan amount, interest rate, and term. See how different rates and terms affect your monthly costs and total repayment amount.
UK Mortgage Affordability Calculator
Find out how much you can borrow based on your income, outgoings, and deposit. Understand lender affordability criteria and see what property price range you can consider.
Mortgage Repayment Calculator
Work out your monthly repayment amount and see how it changes with different interest rates or loan terms. Compare repayment scenarios to find the option that works for you.