SA302 Explained: Your Tax Calculation Document for 2026/27

Quick answer

An SA302 is HMRC's tax calculation document for one tax year. It summarises your total income, the allowances applied, the Income Tax and National Insurance due, and the final amount owed or refunded -- all drawn from your Self Assessment return. Lenders treat it as official proof of declared income, especially for self-employed people and company directors. You download it from your HMRC online account.

What an SA302 actually is

The SA302 is not a separate tax you pay or a form you fill in. It is a printable summary that HMRC generates automatically once you have submitted a Self Assessment return. Think of it as the receipt for your tax position: it restates the income you reported, applies the relevant allowances and rates, and arrives at a single figure of tax due.

Because it is produced by HMRC from your own declared figures, third parties trust it far more than self-prepared spreadsheets or raw bank statements. That is why it has become the standard evidence of income for the self-employed, particularly when applying for a mortgage.

The name comes from the old reference code for the tax calculation page. You will sometimes see it called a "tax calculation" or "tax computation" -- for practical purposes these are the same document.

What the SA302 contains, line by line

The layout varies slightly year to year, but the logic is always the same: start with income, subtract allowances, apply rates, add National Insurance, and finish with the balance.

For 2026/27, the Personal Allowance is GBP 12,570 and is frozen at that level until April 2028. It is tapered away by GBP 1 for every GBP 2 of income above GBP 100,000, disappearing entirely at GBP 125,140 -- which creates an effective 60 percent marginal rate across that band. Income Tax for England, Wales and Northern Ireland runs at 20 percent on income between GBP 12,571 and GBP 50,270, 40 percent up to GBP 125,140, and 45 percent above that. Scotland has its own bands, so a Scottish taxpayer's SA302 will reflect the Scottish rates instead.

Self-employed income on the SA302

For a sole trader, the headline number is your trading profit -- turnover minus allowable expenses. The SA302 then applies the Personal Allowance and Income Tax bands, and adds Class 4 National Insurance: 6 percent on profits between GBP 12,570 and GBP 50,270, then 2 percent above GBP 50,270 for 2026/27. Voluntary Class 2 at GBP 3.65 per week may also appear if you have chosen to pay it to protect your State Pension and benefit record; profits below the Small Profits Threshold of GBP 7,105 are where that choice usually matters most.

If you want to sanity-check the tax and NI figure on your own SA302, model it first.

Dividends and director income

Company directors who take a small salary and the rest in dividends will see the dividend income on their SA302. For 2026/27 the dividend allowance is GBP 500, and dividends are taxed at 10.75 percent, 35.75 percent and 39.35 percent depending on which band they fall into -- rates that rose by two points for this tax year. Because dividends are declared through Self Assessment, the SA302 captures them, which is why directors as well as sole traders rely on it as proof of income.

How to get your SA302 from HMRC

The route depends on how you filed.

1. Filed through HMRC online Self Assessment. Log in to your HMRC account, open the relevant tax year, and select the option to view or print your tax calculation. This is your SA302. You can do this for any year you filed this way.
2. Filed with commercial software. HMRC often will not display an online SA302 for software-filed returns. Instead, print the tax computation from the software you used -- it is accepted in the same way.
3. Filed by an accountant. Ask your accountant to print the tax computation from their software and to pull your tax year overview from their agent account.

In every case you should also download the tax year overview, a separate one-page HMRC document. The overview confirms the tax charged and the payments recorded against your account. Lenders want it because it corroborates that the SA302 figures match HMRC's records.

Why mortgage lenders ask for it

When you are employed, a lender can read your income straight off payslips and a P60. When you are self-employed, there is no employer to vouch for you, so the lender turns to the document you cannot quietly inflate: the tax calculation you filed with HMRC.

The SA302 plus tax year overview does two jobs. It proves the level of income you declared, and it proves you actually declared it. A spreadsheet showing strong profit means little if it was never reported to HMRC. The SA302 closes that gap.

Most lenders ask for two or three years. Two years is common for an established trader; some will work with one year given a solid track record, while others prefer three for newer businesses. Lenders also look at the direction of travel. A profit that is rising steadily is reassuring; a sharp drop in the latest year may prompt questions, and many lenders will average the figures or lean on the lowest year.

If you are working out what you can borrow against your declared profit, start with the affordability picture.

Common SA302 problems and how to avoid them

The figures do not match across documents. The income on your SA302 must reconcile with your tax year overview. If they differ, it usually means the return was amended after the overview was generated, or the overview has not refreshed. Re-download both and check the dates.

You filed late or have not filed yet. You cannot produce an SA302 for a year you have not submitted. If a mortgage application is looming, filing earlier in the year rather than at the January deadline gives you the documents you need in good time.

Software return, no online SA302. This catches people out. If HMRC shows nothing under the tax calculation for a software-filed year, that is expected -- use the software computation and the HMRC tax year overview together.

Discrepancies with declared affordability. If your day-to-day spending implies a higher income than your SA302 shows, a lender may probe it. The honest fix is to make sure your return reflects your true profit in the first place. To see how a given profit converts into take-home income, model it.

How the SA302 fits the wider 2026/27 tax picture

The SA302 only reflects the income types you actually had, but it sits within the full Self Assessment framework. A few 2026/27 figures worth keeping in mind when you read or plan around your calculation:

The trading allowance of GBP 1,000 matters for very small side incomes: if your gross trading income is at or below it, you may not need to declare it at all, in which case there is no SA302 to produce for that activity. Once you cross it, you are into Self Assessment territory and the SA302 becomes available.

Things the SA302 does not directly settle -- such as Capital Gains Tax on an asset sale, or how pension contributions reduce your adjusted net income -- are handled elsewhere on the return and through reliefs. For those, work the specific mechanism rather than reading it off the tax calculation. If a number is not on your SA302, it is because that part of your tax was either not relevant or dealt with separately.

Final word

An SA302 is simply HMRC's tidy summary of what you told them you earned and what tax that produced. Its value lies in being official and hard to dispute, which is exactly why mortgage lenders and other institutions ask for it. Keep two to three years filed and downloaded, always pair each one with its tax year overview, and check the figures against a calculation of your own before you hand them over. Get those habits right and the SA302 stops being a hurdle and becomes one of the most useful documents a self-employed person owns.