See every tax, insurance and contract deadline this month at a glance.
For sole traders and small firms who got caught out once too often by a date they forgot. HMRC deadlines, CIS returns, VAT, insurance renewals, all in one view.
September
📅 Tax & Filing
- Start thinking about your Self Assessment return. Gather your CIS statements (CIS301s), bank records, and expense receipts.
📋 Business Admin
- CSCS renewal if expiring before Christmas — book the HS&E test early, slots fill up in Q4.
🌤️ Seasonal Tips
- Autumn work picks up. Darker evenings mean adjusting site lighting and checking visibility PPE.
Full Year Overview
📅 Monthly reminder
Check this page on the 1st of each month. Set a recurring reminder in your phone — 2 minutes to stay on top of everything.
What the law actually says
- •HMRC late-filing penalties for self-assessment start at £100 the day after 31 January and escalate to daily penalties from 3 months on.
- •CIS returns are due by the 19th of every month. £100 minimum penalty per missed monthly return, even if there's nothing to declare.
- •VAT returns are quarterly and due one month and 7 days after the quarter end. Surcharges run on a sliding scale up to 15% of the VAT due.