Common accounting mistakes South African small businesses make, and how to avoid them
Most accounting problems are habits, not mysteries. These are the mistakes that most often lead to penalties, wrong tax and cash shortages, each with a fix you can start this month.
In short
- The costliest mistakes are timing mistakes: late returns, late payments and late records.
- SARS charges interest of 10.25% a year on late or underpaid tax, on top of penalties.
- Underestimating provisional tax by more than 20% brings a penalty.
- A business bank account, a monthly reconciliation and a diary of tax dates prevent most of the list.
1. Mixing personal and business money
The cost: you cannot tell what the business earns, and you cannot prove which expenses were for the business. The fix: open a separate business account, pay yourself a set amount on a set date, and stop using the business card for personal spending.
2. Not reconciling the bank
The cost: errors, duplicate payments and fraud go unnoticed for months. The fix: match every bank line to your books at least monthly, and investigate every difference the same day you find it.
3. Missing tax dates
The cost: penalties, plus interest at 10.25% a year on late or underpaid tax. The fix: put every date in one diary: the monthly employer declaration by the 7th, VAT returns, provisional tax and the annual returns. Ask your bookkeeper to send reminders a week before.
4. Underestimating provisional tax
The cost: SARS charges a 20% underestimation penalty where your second estimate is below 80% of your final taxable income. The fix: base your estimate on your real year-to-date figures, not last year's, and top up if your income rises.
5. Not watching the VAT line
The cost: registering late means SARS can backdate your registration, with penalties. Staying registered when you do not have to can cost you money too. The fix: check your taxable supplies every quarter against the current thresholds. Our VAT guide explains the new R2.3 million line and how to decide.
6. Keeping poor records
The cost: deductions you cannot prove are disallowed. Tax records must be kept for five years. The fix: capture documents weekly, keep electronic copies, and back them up.
7. Claiming vehicle costs without a logbook
The cost: SARS requires a logbook for business travel. Without it, claims are hard to defend. The fix: record the date, destination, purpose and kilometres of every business trip, from the first day of the tax year.
8. Having no budget or cash forecast
The cost: you find out about a shortfall when it has already happened. The fix: build a simple 13-week cash forecast. Our guide to improving cash flow shows how.
9. Doing everything yourself for too long
The cost: the hours you spend on books and returns are hours not spent on sales, and errors are more likely when nobody checks your work. The fix: hand over the routine work first, such as bookkeeping and payroll, and keep the decisions.
What to do now
- Score yourself against the nine mistakes above, one point for each you make.
- Fix the top two this month.
- Book a bookkeeping review if you scored four or more.
- Set one recurring calendar reminder for the tax dates that apply to you.
Frequently asked questions
What is the most expensive accounting mistake?
Usually a late or missing tax registration or return, because penalties and interest accumulate on top of the tax itself.
Do I need an accountant if I have accounting software?
Software records what you tell it. An accountant checks that what you told it is right, and advises on tax, structure and decisions.
How long should I keep my records?
Five years for tax records, from the date of the return. Companies must keep their company records for seven years.
Sources and further reading
- Budget 2026 Frequently Asked Questions (interest rates, provisional tax penalty, travel allowance logbook), South African Revenue Service
- Tax Administration Act 28 of 2011, section 29 (records), Government of South Africa
This article is general information for South African businesses. It is not tax, legal or financial advice, and it reflects the rules and figures at the date shown above. Tax rules change, so confirm the current position before you act. TBL's practitioners are registered tax practitioners.