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Intermediary use only

Using the Buy to Let Calculator

Easy to find answers to key correct affordability results.

Buy to Let Calculator

Step 1 - ICR calculation

  1. Enter the loan amount needed for this application, including any product fees to be added to the loan
  2. Enter the estimated or current monthly rental income
  3. Choose either a 1-4 year or 5 year fixed term.

Find our Buy to Let products here.

Step 2 - Top Slicing calculation

To see what your client could borrow on a Buy to Let Top Slicing mortgage, we need more information.

Please expand each item below for more information on what to include for our assessment:

Applicant information and finances

Enter the number of applicants and any other adults who are financially dependent upon the applicants. All applicants must live at the same residential address and at least one must be a homeowner.

Enter the number of children under the age of 18. Exclude any children who do not live with the applicants.

The minimum household income for a Top Slicing mortgage is £40,000

Employed client:

  • Include their annual gross basic salary including any occupational pension (the amount before tax and national insurance deductions)
  • We accept 50% of regular additional (non-guaranteed) income such as; overtime, commission and annual or bi-annual bonuses
  • Our underwriters may reduce the amount of reliance on this income at their discretion.

Self employed client:

  • Your client’s business must have been trading for a minimum of three years
  • We’ll assess the last two years’ income and will take an average of the last two years’ SA302’s. If the SA302’s show a decline in income we’ll use the lowest latest year’s figure in isolation
  • For directors with a 25% or greater shareholding we’ll use the latest year’s director’s salary, plus an average of the last 2 years’ dividends.


  • If your client’s retirement is less than 10 years away, and the requested term will extend into retirement, include either their anticipated retirement income or their current income if lower.

If your client also receives:

  • Child maintenance - include the annual amount received. The associated children should be entered in the ‘Number of children’ field as financial dependants. Child maintenance cannot be the only form of income on an application
  • Foster income - average their last two years' earned UK taxable income, or use their most recent year's income if it’s lower than the average. Foster children must be included in the ‘Number of children’ field as financial dependants.

Enter the total amount (combined for joint applicants) your client will continue to pay each month for committed outgoings.


  • Car finance and personal loans
  • Student loans
  • Any loans or credit where your client is acting as a guarantor
  • Second or subsequent charges secured on your client's property
  • Hire purchase commitments
  • Overdraft interest calculated at 2% of the current overdraft balance
  • Credit card/store card/catalogue debts calculated at 3% of the current outstanding balance
  • Childcare costs/child maintenance/alimony
  • School fees
  • Interest costs on any non Buy to Let mortgages your client holds, calculated at 9.04% of the approximate balance at completion. Please don’t include their current residential mortgage.


  • Living expenses (e.g. food, utility bills, clothes, petrol)
  • Subscriptions to leisure activities (e.g. gym or golf club membership)
  • Ground rent, lease payments or maintenance for other properties
  • Pension contributions
  • Commitments, payments or rent that will cease if this mortgage completes
  • Monthly payments for other mortgages, even if they will continue after completion.

Residential mortgage details

If applicant 1 or 2 has an outstanding residential mortgage, please enter the outstanding balance and monthly repayment.

Existing Buy to Let properties

We need to make sure any Buy to Let borrowing is self financing. If it isn’t, any shortfall will be classified as an outgoing.

  • Enter the balance of all Buy to Let mortgages excluding this application. This must include any that are in joint names, and all applications in progress
  • Include any that are in the name of a limited company which your client is a director of.
  • Enter the rental income achieved for all Buy to Let properties, excluding this application
  • Please don't include any rental income already accounted for in your client’s annual income.

Exclusive rates for energy efficient Buy to Lets

Green Buy to Let mortgages are now available with exclusive rates for properties with energy performance ratings A or B.

  • Purchases and remortgages
  • ICR and Top Slicing
See our Green BTL mortgages

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