An SA302 tax calculation is HMRC’s official summary of the income you reported on your Self Assessment return and the tax you owe for that year. If you’re self-employed or earn untaxed income, it’s the document mortgage lenders ask for in place of payslips. You can download SA302s covering the last four tax years through your Government Gateway account, or request paper copies by phone.1GOV.UK. Get Your SA302 Tax Calculation
What the Document Shows
An SA302 breaks down every figure that feeds into your tax bill. HMRC lists your total income on which tax is due, any allowances and reliefs you claimed, the total amount owed for the tax year, and the working that produced that figure.2GOV.UK. Understand Your Self Assessment Tax Bill: Tax Calculation (SA302)
In practice you’ll see trading profits, property income, dividends, and interest listed separately, added into a total, reduced by your Personal Allowance, and then taxed at the relevant bands.3GOV.UK. Income Tax Rates and Personal Allowances The single figure at the bottom is your total tax liability for the year. That’s the number lenders focus on, because it’s what they compare against your reported income to see whether the picture is coherent.
Downloading Your SA302 From HMRC Online
You’ll need a Government Gateway account and your ten-digit Unique Taxpayer Reference. Once signed in:
- Open Self Assessment from your tax account, then choose “More details about your Self Assessment returns and payments.”
- Select the tax year you want a calculation for.
- Save the SA302 as a PDF or print it from your browser.
There’s a timing rule that catches people out. You cannot print or download an SA302 until 72 hours after you submitted the underlying tax return.1GOV.UK. Get Your SA302 Tax Calculation If a lender needs the document by Monday and you filed on Thursday evening, that window becomes a real problem. File early enough to leave yourself room.
The portal keeps the last four tax years available.1GOV.UK. Get Your SA302 Tax Calculation Anything older, you’ll have to ask HMRC for directly. It’s worth saving each year’s PDF the moment it becomes available so you don’t have to rely on the portal later.
Getting a Paper Copy by Phone
Some lenders specifically want an SA302 printed on HMRC-headed paper, and not everyone can use the online portal. Call the Self Assessment helpline on 0300 200 3310 and ask HMRC to post the documents to you. This takes longer than downloading, so allow extra time if you’re mid-application. Ask for the Tax Year Overview at the same time and HMRC will send both together.
If You Filed Through Commercial Software
If you use third-party software rather than filing directly on the HMRC portal, the software produces its own tax computation. HMRC publishes a list of recognised suppliers and confirms it accepts valid returns filed through those products.4GOV.UK. Self Assessment Commercial Software Suppliers
Most lenders accept these software-generated versions. Some still insist on the copy pulled from HMRC’s own portal. If a lender rejects a third-party computation, log into your Government Gateway account and download the official SA302 there. The figures will match, because HMRC produces the calculation from the return you filed regardless of the route it took.
Why Lenders Also Ask for a Tax Year Overview
Nearly every mortgage lender asks for a Tax Year Overview alongside the SA302. The two documents do different jobs. The SA302 shows how the bill was calculated from your income. The Tax Year Overview shows whether you actually paid it, listing the total tax due and any payments HMRC has received.
Lenders line the two up and check that the tax due on the SA302 matches the amount on the overview, and that the balance has been paid.1GOV.UK. Get Your SA302 Tax Calculation A matching, paid position gives the underwriter comfort that there’s no hidden tax debt sitting behind your application.
When the Two Documents Don’t Line Up
Mismatches are one of the more common reasons a mortgage application stalls. The cause is often innocent. Savings interest that falls within your Personal Savings Allowance shows up on the SA302 as income but generates no tax, which can make the income figure look inconsistent with what the overview reflects. Some lenders’ automated systems flag this as a discrepancy.
A short letter from your accountant explaining the allowance usually resolves it. The point is catching the issue before it delays completion, which means putting both documents side by side and reading them before you send anything to the lender.
How Many Years You’ll Need
Most mortgage lenders want two or three years of SA302s from self-employed applicants. A few specialist lenders will work with a single year, which helps if you’ve recently gone self-employed, though rates and affordability criteria are usually tighter. Several high-street lenders treat three full years as standard.
Each SA302 needs the matching Tax Year Overview for the same year. Three years of records therefore means six documents in total. Because the portal only holds four years, saving your own PDF each January is a habit worth building.
Filing Deadlines and the 72-Hour Wait
You can’t have an SA302 until you’ve filed the return it summarises. The online Self Assessment deadline is 31 January after the end of the tax year; paper returns are due earlier, by 31 October.5GOV.UK. Self Assessment Tax Returns: Deadlines Missing either date triggers an automatic £100 penalty even if you owe no tax, with further penalties accruing the longer the return is outstanding.
The practical consequence for mortgage timing is straightforward: no filed return, no SA302. Combine that with the 72-hour wait after submission before HMRC will let you download the calculation, and last-minute filing becomes a real risk when a lender is waiting on paperwork.
Fixing a Mistake on Your SA302
You don’t correct the SA302 itself. It’s generated automatically from your return, so if the figures are wrong, you amend the return and a corrected calculation follows.
Amendments can be made online within 12 months of the Self Assessment deadline. A 2023/24 return filed by 31 January 2026, for example, can be corrected up to 31 January 2027. You’ll need to wait at least 72 hours after the original filing before HMRC accepts an amendment, and the updated statement should show within three working days of resubmitting.6GOV.UK. Self Assessment Tax Returns: If You Need to Change Your Return Past the 12-month window, you’ll need to write to HMRC explaining the error and asking for a correction.
What Making Tax Digital Means From April 2026
Reporting rules for self-employed and property income change from 6 April 2026. Making Tax Digital for Income Tax applies to anyone with gross self-employment or property income above £50,000, based on the 2024/25 return. The threshold drops to £30,000 from April 2027 and £20,000 from April 2028.
Instead of a single annual Self Assessment return, affected taxpayers will submit quarterly income and expense summaries through compatible software, followed by a year-end declaration. The first quarterly update for 2026/27 is due by 7 August 2026.
What this will mean for the SA302 specifically isn’t settled. HMRC hasn’t confirmed whether the format changes or whether quarterly submissions will generate interim calculations. If you’re likely to fall within the thresholds, the useful step now is checking that your accounting software is MTD-compatible ahead of April 2026, and keeping in touch with your mortgage broker about what documentation lenders will accept once the new system is live.