Mortgage and Tax Return Calculator UK 2025/26

Reviewed by Mustafa Bilgic
UK Calculator Editor · Updated May 2026

How UK lenders read your tax return when deciding what to lend

If you trade as a sole trader or partner, the assessable income figure UK lenders use is the net profit on your SA302 — not the turnover line. The SA302 is the official summary HMRC produces from your filed Self Assessment, and most lenders also ask for the matching Tax Year Overview that proves the tax has been declared and paid.

For the 2025/26 application season most high-street lenders look at two years of SA302s. Halifax, Nationwide, NatWest and Santander all consider one year of accounts in some cases, particularly if you have a strong deposit and a clean credit file. Specialist lenders like Kensington and Pepper accept one year, but at slightly higher rates.

If profits are rising, the lender takes the lower of (a) the latest year and (b) the two-year average. If profits are falling, almost every lender takes the lower of the two — using the worst figure as the income basis. That is why a sharp drop in year 2 hurts your borrowing far more than a steady performance.

Director-shareholder companies: salary plus dividends or share of profit?

If you trade through a UK limited company and own ≥20% of shares, lenders typically use 'salary plus dividends' from your SA302. A handful — Halifax, Clydesdale, Kensington — instead let you use the company's net profit before tax (sometimes net of corporation tax), which is much higher than dividends actually drawn.

This 'share of net profit' approach can double an applicant's borrowing capacity. The condition is usually that you provide two years of company accounts and the SA302 still backs up your personal income.

Example 1: One-year self-employed plumber, modest deposit

Tom completed his first full year as a self-employed heating engineer. His 2024/25 SA302 shows net profit of £41,000. He has £25,000 saved.

1. One-year-accounts lender: 4.5 × £41,000 = £184,500 max loan
2. With his £25,000 deposit: max purchase price ≈ £209,500
3. LTV: 184,500 / 209,500 = 88% (just inside most one-year-accounts criteria)

Tom would target a £200,000 starter home in Doncaster or Stoke. Adding a guarantor or saving another £8,000 deposit would unlock 85% LTV pricing and a lower rate.

Example 2: Two-year freelancer, profits rising

Aisha is a freelance UX designer. SA302 figures: 2023/24 £52,000, 2024/25 £67,000.

1. Average: (52,000 + 67,000) / 2 = £59,500
2. Latest year: £67,000
3. Lender uses the lower → £59,500 assessable income
4. 4.5 × £59,500 = £267,750 max loan
5. With a £80,000 deposit: max purchase ≈ £347,750 (LTV 77%)

Some lenders (Skipton, Coventry) will use the latest year only if profits have risen consistently — that would lift Aisha's borrowing to £301,500.

Example 3: Limited-company director using share of net profit

Robert is the sole director-shareholder of a small marketing consultancy. His SA302 shows £12,570 salary + £18,000 dividends = £30,570. The company's net profit before tax (per the 2024/25 accounts) is £88,000.

1. 'Salary plus dividends' lender: 4.5 × £30,570 = £137,565 max loan
2. 'Share of net profit' lender (e.g. Halifax): 4.5 × (£12,570 + £88,000 retained share) = up to £452,565 max loan

The choice of lender literally triples Robert's borrowing power. A specialist self-employed broker is usually worth the fee for cases like this.

Common mistakes to avoid

• Using the turnover figure instead of net profit — banks always discount turnover heavily.
• Forgetting the SA302 must match the Tax Year Overview to the penny; a mid-year amendment can delay the application.
• Submitting only one year's accounts to a lender that requires two — automatic decline.
• Including dividends from your own limited company twice (once as PAYE income, once as dividends).
• Adding pension contributions back to net profit; lenders take the figure HMRC sees, not adjusted profit.
• Trying to remortgage in the same tax year as a profit dip — wait until the next SA302 if the trend has reversed.

When to use this calculator

Use this calculator before you instruct a mortgage broker. The output gives you a realistic borrowing range and lets you stress-test how much extra deposit will move you into a lower LTV bracket and a cheaper rate. It is also a useful sanity check after a year of trading in case you need to delay an application.

How this differs in Scotland, Wales and Northern Ireland

The same SA302/Tax Year Overview process applies across England, Wales, Scotland and Northern Ireland because lender criteria are set centrally rather than by region. SDLT (England/NI), LBTT (Scotland) and LTT (Wales) however differ — see the relevant calculators for total purchase costs.

When this calculator is and isn't the right tool

The Mortgage and Tax Return Calculator UK 2025/26 above is built for the most common UK 2025/26 scenarios in this tax area. It will be the right tool when your situation maps cleanly onto the inputs — single property or simple aggregation, standard HMRC rates and bands, and individual taxpayer (rather than complex trust or partnership structures). It is informational and does not replace tailored advice from a chartered tax adviser, especially for transactions above £500,000, cross-border situations, or where reliefs interact with each other. For year-end filings, always reconcile with HMRC's own free calculators on gov.uk before pressing submit on Self Assessment.

Closely related calculators

• Buy to Let Mortgage Calculator — useful when you need a different angle on the same UK property tax topic, especially if your situation involves multiple types of property income or disposal.
• Mortgage Tax Return Calculator — useful when you need a different angle on the same UK property tax topic, especially if your situation involves multiple types of property income or disposal.
• Mortgage Affordability Calculator — useful when you need a different angle on the same UK property tax topic, especially if your situation involves multiple types of property income or disposal.
• Property Purchase Cost Calculator — useful when you need a different angle on the same UK property tax topic, especially if your situation involves multiple types of property income or disposal.
• Self Assessment Tax Calculator — useful when you need a different angle on the same UK property tax topic, especially if your situation involves multiple types of property income or disposal.

Glossary of UK property tax terms

Section 24

The 2017 rule replacing full mortgage interest deduction with a 20% tax credit for individual residential landlords.

SA105

The Self Assessment supplementary form for UK property income.

Box 44

The SA105 box for residential property finance costs (mortgage interest).

Property allowance

£1,000 tax-free band for individual property income, claimable instead of expenses.

Rent-a-Room scheme

Separate £7,500 allowance for letting a furnished room in your main home.

Tax planning checklist

1. Confirm the figures input above match your actual position — purchase contract, mortgage offer or completion statement.
2. Cross-check the year (2025/26) — figures change every April. The tax year 2026/27 starts 6 April 2026.
3. Use HMRC's official calculator at gov.uk for the final filing figure; this calculator is informational.
4. Keep records for at least 6 years — HMRC's normal enquiry window. 21 years for fraud investigations.
5. Discuss any unusual transaction (joint purchase, gift, divorce settlement, trust) with a qualified tax adviser.
6. Submit your return online via Government Gateway — paper deadlines are earlier and penalties harsher.