TaxFlow Pro

About TaxFlow Pro

Stop dreading your self-assessment. TaxFlow Pro calculates your UK tax bill in seconds — income tax, Class 4 National Insurance, payment on account, and exactly what you owe HMRC by January 31st and July 31st.

Enter your income, expenses, and any reliefs. The app gives you a full breakdown instantly: personal allowance, taxable profit, each tax band, your NI contributions, and a clear payment schedule. Switch between 2024/25 and 2023/24 tax years with one click.

What it calculates

• Self-employment profit after allowable expenses
• Income tax across basic, higher, and additional rate bands
• Dividend income at the correct dividend tax rates
• Class 4 National Insurance (2024/25: 6% / 2%; 2023/24: 8.85% blended)
• Personal allowance including the £100k taper
• Pension contribution relief and Gift Aid band extension
• PAYE tax credit for employed + self-employed individuals
• Payment on Account — what's due January 31st vs July 31st

Like all Nexior Gray products, TaxFlow Pro is a single HTML file — open it in any browser and it works immediately, offline, with no installation, no account, and no subscription. Buy once and it's yours.

For estimation purposes only. Always verify your final figures with HMRC or a qualified accountant. Rates apply to England, Wales, and Northern Ireland residents.