Financial planning: Maximum Buy to Let loan calculator

Buy to Let borrowing tool

Maximum Buy to Let loan calculator

Estimate how much you may be able to borrow based on expected rental income and lender stress testing.

⭐ 5.0/5 • 226 Google & Facebook reviews

Regulated by the Financial Conduct Authority · No. 792412

TL;DR

Estimate two common Buy to Let limits

The calculator estimates a rent-supported loan using an ICR and stress rate, then compares it with the selected maximum LTV. It shows the lower figure.

Lenders use different ICRs, stress rates, product rules and property criteria. The result is not a guaranteed loan or Decision in Principle.

Calculator / tool

Maximum Buy to Let loan calculator

How do lenders calculate maximum BTL borrowing?

Lenders usually use Interest Coverage Ratio and a stress rate. This calculator shows the limit based on rental income and maximum LTV.

Details

£1,200
5.5%
125%
75%
£250,000

Stress rate: 7.5%.

Results

Maximum BTL mortgage
£153,600
at 75% LTV i ICR 125%
Limit by ICR£153,600
Limit by LTV (75%)£187,500
Minimum deposit£96,400
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Need a more accurate estimate?

Calculators show indicative figures. An adviser can check realistic options after reviewing your situation.

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How lenders assess Buy to Let borrowing

Many BTL lenders test whether expected rent covers stressed mortgage interest by a required percentage. They also cap the loan at a maximum LTV and assess the applicant, property, tenancy and valuation.

  • ICR is the required rental-interest coverage.
  • Stress rate is a notional rate used in the test.
  • Maximum LTV limits the loan against property value.
  • The lowest applicable limit normally controls the estimate.

Personal name, limited company and taxpayer status

Some lenders use different ICR or stress assumptions by tax band, ownership structure and product type. Limited-company lending is not automatically more suitable and needs separate mortgage, accounting and tax review.

What the maximum loan estimate does not include

The tool does not model lender affordability top-slicing, minimum income, portfolio-landlord rules, property restrictions, valuation rent, licensing, lease terms, credit profile, fees or underwriting.

Example maximum BTL loan

With £1,200 monthly rent, 125% ICR and a 7.5% stress rate, the rental test produces one limit. A 75% LTV on a £250,000 property produces another; the lower figure is shown.

Monthly rent
£1,200
ICR
125%
Illustrative stress rate
7.5%
Maximum LTV
75%

Frequently asked questions

What is ICR in Buy to Let lending?

Interest Coverage Ratio compares expected rent with stressed mortgage interest. A 125% requirement means rent must be at least 125% of the tested interest amount.

What is a Buy to Let stress rate?

It is a notional interest rate used to test rental coverage, not necessarily the pay rate. It varies by lender, product, deal period and applicant or ownership structure.

Why can another lender offer a different maximum loan?

Lenders use different ICRs, stress rates, LTV caps and property rules. Some may consider personal income through top slicing, while others will not.

Does taxpayer status affect the result?

It can. Some criteria distinguish basic-rate and higher-rate taxpayers or personal and limited-company applications. The calculator lets you select an ICR but does not determine the correct one for you.

Is this a guaranteed Buy to Let mortgage amount?

No. It is an estimate based on selected assumptions. Valuation, expected rent, credit profile, experience, income and full underwriting still apply.

Can a limited company borrow more?

Sometimes criteria differ, but a higher estimate does not make the structure suitable. Compare mortgage pricing, fees, tax, accounting and long-term plans with qualified advisers.

The results are estimates only and are not a mortgage offer, mortgage advice or a guarantee of lending. Actual borrowing, costs and monthly payments depend on lender criteria, product fees, credit profile, property type and full underwriting.

Buy to Let tax treatment depends on your circumstances. Speak to a qualified tax adviser or accountant for tax advice.

Client Reviews

What our clients say

5.0
226 reviews
Google
Verified reviews
S
Sylwia Zgórska
17/03/2026
Google · Translated from Polish
Mortgage + Insurance

"I highly recommend Mariusz Wasiluk (mortgage broker) and Magdalena Kurowska (insurance). We had great communication with them from start to finish. They explained everything clearly, were very helpful, and thanks to them the whole process was much less stressful. Great cooperation!"

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Working hours
Mon–Fri 9:00–18:00 Evenings and weekends by arrangement
We cover
Whole UK — 100% remote

Extend Finance is a mortgage broker regulated by the Financial Conduct Authority. Our registration number is 792412 — you can verify this at register.fca.org.uk

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