Auto-assessment has made tax season feel simpler for a lot of people. SARS gathers information from employers, medical schemes, retirement funds and financial institutions, calculates what it believes you owe, and presents you with an assessment you can accept with a single click. For a straightforward taxpayer with one income and no deductions, that’s a reasonable shortcut.
The problem is that an auto-assessment only knows what third parties have told SARS. It does not know about the expenses you haven’t reported anywhere else, and accepting one without checking it is one of the most common ways taxpayers end up paying more tax than the law actually requires.
What an auto-assessment can see, and what it can't
SARS builds the auto-assessment from data submitted by employers (your IRP5), medical schemes, retirement annuity providers, and banks. That’s a reasonably complete picture for income. It is a much less complete picture for deductions, because most deductions depend on information only you hold.
Here is what typically falls outside the data SARS already has:
- Home office expenses, if you work from home and meet the requirements
- Rental property expenses, including the costs of maintaining and financing a property you let out
- Out-of-pocket medical expenses, above what your scheme paid, which are deductible in specific circumstances
- Retirement annuity contributions, made outside of a payroll deduction
- Travel claims, for taxpayers who receive a travel allowance and keep a logbook
- Donations to registered public benefit organisations, where you hold a section 18A certificate
If any of these apply to you and you accept the auto-assessment without adjusting it, you are voluntarily paying tax on income that could legitimately have been reduced.
The other direction: what if it understates your income?
It cuts both ways. If you earned freelance income, rental income, or investment income that wasn’t reported to SARS by a third party, an auto-assessment built purely from what SARS already has will simply miss it. Accepting an assessment that understates your income does not make the omission disappear it creates an understatement that you remain legally responsible for, and one that can surface later as a verification or an audit with penalties attached.
What to actually do with an auto-assessment:
- Don't accept it immediately, You have a limited window to make changes before it's treated as final, so check it within that window rather than after.
- Compare it against your own records, your payslips, medical scheme statement, rental income and expenses, retirement contributions, and any other income you received during the tax year.
- If it's missing deductions you're entitled to, you can edit and resubmit the return with the correct information before the deadline.
- If it understates your income, correct it yourself. Voluntary correction, made before SARS finds the gap, produces a considerably better outcome than having SARS identify it first.
- If your affairs are genuinely complicated, multiple income sources, rental property, investments, or income earned in more than one country an auto-assessment is rarely going to reflect your actual position, and it's worth having it reviewed properly rather than guessed at.
Frequently asked questions
Not always. SARS sets out annually which taxpayers are not required to submit, based on income level and the nature of the income. Even where submission isn't required, it's often worth submitting anyway if you have deductible expenses a refund is never paid on a return that was never filed.
Once the window closes, the auto-assessment becomes a final assessment like any other, and correcting it means going through the normal request for correction or objection process rather than a simple edit.
If your affairs are genuinely simple one salary, no property, no investments, no side income probably not. The value shows up precisely where the affairs stop being simple, which is a large share of taxpayers who assume their auto-assessment is more accurate than it actually is.
This article is general information about South African tax and is not tax advice. Tax outcomes depend on the specific facts of each matter. See our Website Terms of Use for more.
Unsure about your auto-assessment?
Rental income, investments, multiple income sources, or foreign income? A proper review is a straightforward starting point.