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Tax Filing Software

Tools to help you complete and submit your self assessment return.

If you’re a UK sole trader, you need to file a self assessment tax return every year - and the software you use to do it can make the process significantly easier. Tax filing software guides you through your return step by step, calculates your tax bill, and submits directly to HMRC. It won’t replace knowing roughly what you’re doing, but it removes a lot of the guesswork. This category covers tools at every price point, from HMRC’s own free service to step-by-step guided apps to professional-grade desktop software.

What to look for

• Price vs complexity - if your affairs are straightforward (one income source, standard expenses), a simple low-cost option like GoSimpleTax or Untied will do the job. If you have property income, multiple income sources or foreign income, you may need something more capable like TaxCalc.

• MTD for Income Tax compatibility - Making Tax Digital for Income Tax is live for sole traders from April 2026. If you’re thinking ahead, check whether the software is already HMRC-recognised for MTD. GoSimpleTax, Untied and TaxNav are all on the list.

• Guided vs manual - some tools walk you through the return with questions; others present you with blank boxes. If self assessment is new to you, guided software is much less daunting.

• App vs desktop vs browser - worth checking before you commit. TaxCalc is desktop software; TaxNav runs in the browser with nothing to install; Pie Tax and Untied are mobile-first.

• Managed filing option - if you’d rather hand the whole thing to someone qualified, Taxfix offers a fixed-fee accountant-managed service.

Some links on this page may be affiliate links. If you sign up or purchase via one of these links we may earn a small commission, at no extra cost to you. This does not affect which tools are listed or how they are described. Read our affiliate disclosure here.

GoSimpleTax

Simple self assessment software designed specifically for UK sole traders and individuals. Guides you through your return step by step.

Best for: Sole traders who want to file their own return without an accountant.

Pricing: Paid - from £69.99 per year

Free trial: Yes

MTD compatible: Yes

Mobile app: Yes

UK specific: Yes

Visit GoSimpleTax

Taxfix

Managed self assessment service — a qualified accountant files your return for you at a fixed price.

Best for: Sole traders who want a hands-off, accountant-managed filing experience

Pricing: Paid - from £99 per return

Free trial: No

MTD compatible: No

Mobile app: Yes

UK specific: Yes

Visit Taxfix

Pie Tax

App-based self assessment filing for sole traders and employees. Newer entrant with a clean, modern interface.

Best for: Tech-savvy sole traders and side hustlers

Pricing: Free basic / paid tiers

Free trial: N/A

MTD compatible: Yes

Mobile app: Yes

UK specific: Yes

Visit PieTax

HMRC Free Online Service

HMRC's own free self assessment filing service. No frills but completely free and officially supported.

Best for: Anyone who wants to file for free and has straightforward affairs

Pricing: Free

Free trial: N/A

MTD compatible: N/A

Mobile app: No

UK specific: Yes

Visit HMRC

TaxCalc

Professional-grade tax return software used by accountants and individuals with more complex affairs.

Best for: Sole traders with more complex returns or those who want desktop software

Pricing: Paid - from £42 per year

Free trial: Yes

MTD compatible: No

Mobile app: No

UK specific: Yes

Visit TaxCalc

TaxNav

Browser-based MTD for Income Tax software. No downloads or installation required. Developed by the same team that created MTD for VAT.

Best for: Sole traders who want a simple browser-based MTD filing tool with no software to install

Pricing: Paid - from £60 +VAT per year

Free trial: Yes

MTD compatible: Yes

Mobile app: No

UK specific: Yes

Visit TaxNav

Untied

App-based self assessment and MTD software, covers sole traders and landlords.

Best for: Sole traders with straightforward income who want a modern app-based filing experience

Pricing: Paid - from £64.99 per year for self assessment / £129.99 for MTD tier

Free trial: Yes

MTD compatible: Yes (higher paid tier)

Mobile app: Yes

UK specific: Yes

Visit Untied

There’s no single best option here - it depends on how complex your tax affairs are and how much you want to spend. For most straightforward sole trader returns, a guided app in the £0-£70/year range will be perfectly sufficient. If you’re approaching the MTD for Income Tax threshold, prioritise tools that are already HMRC-recognised for quarterly submissions.

Last reviewed: June 2026