SA302 Calculation: What Lenders Actually Check

A mortgage application can move quickly until a lender asks for an SA302 calculation. For self-employed people, landlords, CIS subcontractors and company directors, this is often the point where income needs to be shown clearly, not just explained. Knowing what the document says, where the figures come from and what a lender is likely to question can prevent last-minute delays.

An SA302 is not a separate tax return and it is not something you should try to recreate from scratch. It is HMRC's calculation of the tax due from the information submitted on your Self Assessment return. Used alongside the Tax Year Overview, it gives lenders evidence of declared income and confirms whether the tax position shown has been paid or remains outstanding.

What is an SA302 calculation?

The SA302 calculation is generated after a Self Assessment tax return has been submitted and processed by HMRC. It sets out the income used for the tax calculation, allowances claimed, tax due and payments made or due.

For a sole trader, the document will normally show trading profits rather than the total amount invoiced to customers. That distinction matters. If you turn over £80,000 but have £25,000 of legitimate business expenses, your taxable trading profit is £55,000. It is the profit figure, along with any other declared income, that is relevant to the calculation.

For a landlord, it will reflect rental profit after allowable property expenses. For a CIS subcontractor, it should include the self-employment income declared and CIS deductions suffered, which may reduce the final tax bill or create a refund. If you also have employment income, dividends, savings interest or pension income, these can appear too.

The SA302 is particularly useful because it is produced from a return already filed with HMRC. A lender is therefore looking at evidence of declared income, rather than an informal estimate or a set of accounts that has not yet fed through to the tax return.

SA302 calculation versus a Tax Year Overview

These documents are often requested together, but they do different jobs.

The SA302 calculation explains how HMRC arrived at your Income Tax and National Insurance position for a tax year. It shows the sources of income, deductions and tax calculation. The Tax Year Overview is a separate HMRC record that shows what has been charged to your Self Assessment account and what has been paid.

A lender may ask for both because an SA302 on its own does not prove the tax due has been settled. If there is an amount outstanding, that is not automatically a reason for a mortgage to be declined. However, it can lead to questions, particularly if the balance is large, overdue or suggests pressure on cash flow.

Where possible, provide the documents for the same tax years and check that the figures are legible and complete. Sending a screenshot with half a page missing, or an old calculation that does not match the lender's request, creates avoidable work at a stage when timing can matter.

Which income figures do mortgage lenders use?

There is no single answer because every lender has its own underwriting rules. Many want two or three years of SA302s and may use an average of profits, the latest year's figure, or the lower figure where income has fallen. Some are more flexible for applicants with a strong track record in the same trade or profession.

For sole traders and partnerships, lenders commonly focus on taxable profit. This can feel frustrating if your accountant has helped you claim every allowable expense, because good tax planning can reduce the income used for affordability. That does not mean claiming expenses is wrong. It means a mortgage plan should be considered before the application, not after the tax return has been filed.

For limited company directors, the position is more nuanced. Some lenders assess salary and dividends only. Others may consider a share of retained profit, especially where the director owns a substantial part of the company and profits are being retained for a sensible business reason. The lender's policy, the company's accounts and the consistency of income all matter.

CIS subcontractors can encounter another layer of confusion. CIS deductions are payments made towards tax and National Insurance, not evidence of net income. A lender will generally want to understand the taxable profit shown on the SA302, while payslips, deduction statements, bank records or accounts may be requested to support the wider picture.

How to get your SA302 from HMRC

If you submit your own Self Assessment return through HMRC's online service, you can usually print or save the SA302 calculation after filing. You can also access the Tax Year Overview through your Personal Tax Account. HMRC has previously provided printed copies by post in some circumstances, but digital copies are generally the practical route.

If an accountant submits your return using commercial software, they can normally provide a tax calculation produced from the submitted return. Most mainstream lenders and brokers accept accountant-generated calculations, but requirements do vary. It is worth checking exactly what format is required before sending documents.

Do not confuse the SA302 with a Self Assessment return, annual accounts, a tax demand or a CIS statement. Each has a purpose, but they are not interchangeable. If the lender says SA302 and Tax Year Overview, give them those documents first.

Why the figure can look lower than you expected

The most common surprise is the gap between money coming into the bank and taxable income. Turnover is not profit, and business banking is not a personal payslip.

A taxi driver may have significant costs for vehicle leasing, fuel, insurance, repairs, licensing, radio fees and card processing charges. A construction subcontractor may pay for tools, protective equipment, mileage, accountancy fees and other costs of doing the job. These expenses can be allowable and commercially necessary, but they reduce taxable profit.

There can also be timing differences. An unusually quiet year, a period off work, a large one-off expense or the first year of trading may make the latest SA302 less representative of normal earnings. Explain the background to your broker or lender early and keep supporting records available. A clear explanation backed by accounts is more useful than a rushed explanation after an underwriter raises a query.

Preparing for a mortgage or remortgage

If borrowing is on the horizon, start looking at your accounts and tax position at least a year ahead. You cannot simply alter historic income because a lender would prefer a higher figure. But you can make informed decisions about expense claims, pension contributions, dividends, retained profits and the timing of major purchases with advice that takes your wider plans into account.

Keep bookkeeping up to date. Late records often lead to late tax returns, rushed calculations and missing documents just when a mortgage offer needs renewing. Reconcile business income, retain receipts, separate personal and business spending where possible, and file on time. These habits also make it easier to spot whether profits are growing, stable or under pressure.

It is equally sensible to check your SA302 before sharing it. Confirm the name and tax year are correct, review the profit figures against your accounts and make sure the Tax Year Overview reflects payments properly. If an error was made on the return, deal with it through the proper amendment process rather than hoping it will not be noticed.

Common SA302 calculation problems

A newly self-employed applicant may only have one completed tax year, while a lender requires two or more. In that case, the choice of lender becomes particularly important, and extra evidence such as contracts, accounts or prior employment history may help depending on the case.

Falling profits are another common issue. Lenders are usually cautious when the most recent year is lower than the year before, even if the earlier figure was strong. A genuine reason, such as illness, a planned reduction in work or a one-off cost, may be relevant, but it needs to be credible and supported.

Outstanding tax can also cause concern. Paying a bill shortly before applying does not erase the fact that it was due, but keeping Self Assessment payments under control gives a better picture of financial management. If you cannot pay in full, address it early rather than ignoring HMRC correspondence.

For directors, a mismatch between salary, dividends, company accounts and personal tax returns can slow down underwriting. Make sure the records tell the same commercial story. This is especially important where profits have been retained in the company or dividends have changed significantly.

An SA302 calculation is a snapshot of income reported to HMRC, but a good application is built on more than one document. With tidy records, timely returns and advice that reflects how you actually earn, you can approach a lender with figures you understand and can stand behind.