Mortgage illustration (ESIS)
Last checked UK · illustrative onlyNot a lender or brokerAboutDisclaimer
Published by Rodway Labs — not a mortgage adviser
Published · Last revised
Mortgage illustration (ESIS): The personalised quote document for one specific deal, issued before you apply or when an offer is made. In the UK its required format is the ESIS (European Standardised Information Sheet), which sets out rate, payments, fees and early repayment charges in a fixed order.
It is specific to the deal and loan amount quoted. It is the document to compare, not an advert or a phone quote. It is not an offer: the deal is only agreed when the lender issues a formal offer, and rates can be withdrawn before then.
UK illustrations may be headed ESIS or Key Facts Illustration (KFI). The FCA’s mortgage rules (MCOB 5A) brought in the ESIS from 21 March 2016. Lenders could keep using the older KFI until 20 March 2019, and the ESIS has been compulsory since 21 March 2019. That is why older paperwork may say KFI while current offers say ESIS. Because the format is standardised, the sections appear in the same order whichever lender issues it.
Example: checking an illustration against the calculators
- Illustration says
- £185,000 over 22 years at 5.97%, £999 product fee, £250 cashback
- Monthly payment you should see
- about £1,260 (mortgage repayment calculator)
- Add costs not on it
- £500 legal costs, making £1,499 fees and £1,249 net
- True cost with the 2% ERC still live (4 months left)
- about £5,319 more than staying (4.19% for 4 months, then a 6.22% product transfer) over 24 months
- Same deal once the ERC has ended
- about £329 behind a fee-free 6.22% product transfer over 24 months
Illustrative only. If your calculator payment is far from the illustration’s, check the term, the repayment type and whether fees have been added to the loan. Small differences are normal because lenders’ interest conventions vary.
How it affects a remortgage
The illustration puts fees, early repayment charges and the follow-on rate beside the rate, so it is the right place to start a comparison. In the example, the same illustration is a clear no while the old charge is live and a close call once it has ended.
Read the fee and ERC lines before the rate. They are fixed sums or rules, whereas a rate gap only adds up month by month.
Keep an illustration for every option, including a product transfer, so you compare like with like over the same period. Check the expiry date on each.
Example: checking an illustration against the site maths
- Instalment at 5.97% on £185,000 over 22 years
- about £1,260.41 a month
- Interest over 22 years if 5.97% applied throughout
- about £147,748
- Total repaid on that basis
- about £332,748 (about £1.80 per £1 borrowed)
- What a real illustration adds
- the follow-on rate after the deal, so its total will be higher
Illustrative only. The site uses one rate for simplicity; the lender’s illustration uses its own rate path and fees.
Common mistakes
- Reading only the first page. The ERC, fees and flexible features sit further in.
- Using one ESIS to compare products. The rules say an ESIS should cover one mortgage only, so ask for one per deal.
- Comparing totals across different terms. A longer term lowers the payment and raises the total.
- Ignoring the validity date. Illustrations and rates can expire.
- Paying fees before reading it. MCOB 5A says a firm must not take product-related fees before you have had a chance to consider the ESIS.
- Comparing two illustrations with different fees treated differently. If one adds the fee to the loan and the other has it paid upfront, the totals are not like for like until the fee is counted the same way in both.
Edge cases
- Reflection period. The ESIS states the time you have to reflect before committing.
- Revised versions. A material change to the terms, for example a different product or an added charge, means a revised ESIS.
- Direct deals. The rules let a firm skip the ESIS for what the FCA defines as a “direct deal”, so a quick online switch may come with a different document.
- Older paperwork. A Key Facts Illustration from before March 2019 carries the same information in a different order.
- Fees added to the loan. The illustration then shows a higher loan amount and a higher total.
- Interest-only borrowing. The ESIS has to state the amount you will still owe at the end of the term on any interest-only part.
- The follow-on rate. The FCA notes the rate after a deal is often the SVR but can be another type of rate, and is typically higher; the illustration shows which rate applies and what the payment becomes.
Where to go next
- How to read an illustration — section by section.
- True-cost calculator — type the illustration fields in.
- Mortgage repayment calculator — check the monthly payment.
- How much does it cost to remortgage? — the fee lines to check.
Sources checked 2 November 2026
- FCA Handbook MCOB 5A (ESIS rules) — what an ESIS must contain, when it must be given, and how the APRC and early repayment sections are completed.
- MoneyHelper: choosing a mortgage — shopping around, advice and execution-only routes, and what the paperwork shows.
- FCA: support with mortgages and interest rates — offers typically valid 3 to 6 months, reversion rates, same-lender switches, ERCs and stress testing.
- MoneyHelper — independent, government-backed guidance on remortgaging, fees and switching deals.
Figures marked example are illustrative only, not a quote and not lender, broker or FCA-regulated advice. Definitions are plain English for this site, not the wording in your offer. The definitions and explanations are in our own words. Last checked 2 November 2026.