How to Prepare for Self Assessment Season: A Checklist for Small Business Owners

Self Assessment season doesn’t have to be stressful. With a little planning and the right support, you can breeze through your year-end obligations and focus on what you do best, running your business. Here at Numberwork Services we’ve put this checklist together for you, to help you get organised and confident for tax time.

1. Gather Your Financial Records

• Collect all invoices, receipts, and expense records for the year
• Download bank and credit card statements
• Ensure all digital and paper records are organised and accessible

We recommend doing this on at least a monthly basis, so that you’re not in a mad panic at the end of the year. Plus if you fall under the criteria for Making Tax Digital (MTD) you need to be submitting quarterly submissions not annual submissions.

2. Update Your Bookkeeping

• Reconcile your accounts (bank, credit card, PayPal, etc.)
• Check that all income and expenses are recorded accurately
• Chase up any missing paperwork from suppliers or clients

Again this should be a monthly occurrence. By keeping on top of your bookkeeping consistently you can identify any discrepancies in good time. This makes your bookkeeping much easier to manage than trying to untangle it all at the last minute. If you’re doing your bookkeeping yourself, and you’re finding it hard to make the time for it, then maybe that’s one thing you should be delegating.  

3. Review Your Expenses

• Categorise expenses (travel, office supplies, subscriptions, etc.)
• Identify allowable business expenses to maximise deductions
• Separate personal and business transactions

At Numberwork Services we use Apron to track expenses for our clients. They find it much easier being able to use the Apron app and snap a picture of the receipt or invoice as they receive it. This way there’s no missing paperwork to worry about and you can be sure every tax deductible expense is accounted for.

4. Check Payroll and Contractor Payments

• Ensure all payroll records are up to date and compliant
• Gather P60s, P45s, and pension statements if applicable
• Confirm payments to contractors and collect any necessary documentation

Payroll can be a tricky and complex process so just make sure you’re up to date with all the latest regulations. If you find that a tad overwhelming then seek assistance from a professional payroll provider, like us here at Numberwork Services. 

5. Prepare for Year-End Adjustments

• Review outstanding invoices and unpaid bills
• Write off any bad debts if needed
• Account for stock/inventory and assets

If you find the prospect of chasing debt scary, why not set up automatic email reminders? This of course means, you need to keep on top of your bookkeeping reconciliation so that you’re not chasing people who have already paid.

6. Organise Tax Documents

• Be aware of deadlines – submission and payment by 31st January and your next payment on account by 31st July. Of course these dates will change to quarterly with MTD, so keep up to date with the changes.
• Gather details of any grants, loans, or reliefs received
• Ensure any travel mileage has been logged

Every expense counts when it comes to your tax bill, so be sure you’re keeping a log of all the essential expenses. Ensure you’re aware of deadlines to avoid penalties, interest and fines.

7. Consult Your Bookkeeper or Accountant

• Book an early meeting to review your records and discuss any queries
• Ask about any changes in tax laws or new allowances
• Get advice on tax planning for the year ahead

At Numberwork Services we like to get to know our clients on a personal level and really understand the workings of your business. This way we can be sure that you’re claiming for everything possible to reduce your tax bill.

8. Submit Your Tax Return Early

• File your return ahead of the deadline to avoid last-minute stress
• Double-check all figures for accuracy
• Keep copies of everything you submit

At Numberwork Services we love to get your self-assessment tax return completed in good time. Plus, we don’t want a mad rush, before or after Christmas. As soon as 6th April 2026 is here, we’ll be planning ahead for next submissions.

9. Plan for Next Year

• Set reminders for key tax dates
• Using accounting software or automation tools
• Schedule regular bookkeeping reviews to stay on track

Final Tip:
Don’t leave your self-assessment tax return until the last minute! A little organisation now saves hours of stress later. If you need help, the friendly team at Numberwork Services is always here to support you.