UK Self Assessment Tracker 2025-26 – Sole Trader Income, Expenses & Payments on Account Spreadsheet

Be ready for the 31 January 2027 deadline. Log income for the tax year 6 April 2025 – 5 April 2026, record allowable expenses in the SA103 categories, use simplified expenses for mileage (45p/25p) and working from home, and let the sheet choose between actual expenses and the £1,000 trading allowance. The Summary estimates income tax, Class 4 NIC, the balancing payment and your payments on account, and how much to set aside each month. Key dates, document checklist and a getting started guide included. Excel + Google Sheets, no macros. England, Wales and NI bands by default (editable). Not tax advice.