Sole Trader + PAYE Combined Tax Tracker

If you're employed on PAYE and also run a side business, your tax lives in two places — your employer deducts tax and National Insurance from your wages, while your self-employment is reported separately through Self Assessment, now with Making Tax Digital added on top. The tricky part is that you only get one Personal Allowance across both incomes. This workbook keeps your self-employment records MTD-ready, logs your payslips, and brings the two together into a clearly-labelled year-end estimate.

The ten tabs include:

• Income and Expense Logs mapped to SA103S boxes, with a live quarterly countdown
• A PAYE Payslip Log capturing gross pay, tax and National Insurance per payslip, across multiple employers if needed
• A Combined Year-End & Estimate tab mapping employment figures to SA102 and self-employment to SA103S
• A step-by-step estimate of income tax and Class 4 National Insurance, applying one Personal Allowance across both incomes and crediting tax already paid through PAYE

The estimate uses 2026/27 rates for England, Wales and Northern Ireland, verified against gov.uk, with every assumption listed in plain sight (it excludes pensions, student loan, savings/dividend income and Scottish rates). The maths is proven with two worked examples — a realistic combined year and a high-earner case exercising the 40% and 45% bands and the personal-allowance taper — hand-calculated then independently re-checked. 115 of 115 QA checks pass.

This is a record-keeping tool and estimator, not tax advice and not HMRC-recognised filing software.