What is an online tax return service?

An online tax return service is a platform where you submit your income and expense information (usually by uploading documents or connecting your bank), and a qualified accountant employed by the service files your Self Assessment with HMRC. It's cheaper than hiring a traditional accountant because the platform handles intake and workflow, reducing the accountant's time per return. You typically get the filed return for review before submission, but less ongoing tax advice than a retainer accountant would provide.

How much does an online tax return service cost?

Most UK online tax return services charge £100–£300 for a sole trader Self Assessment. Simple returns (one income source, trading allowance) sit at the lower end. Returns with multiple income sources, property income, or capital gains cost £200–£350. Limited company accounts and Corporation Tax through an online service cost £300–£800. Prices are usually flat-fee per return, not hourly.

Is an online tax return service better than doing it myself?

It depends on complexity. If you have one income source and use the £1,000 trading allowance, HMRC's free online service takes 20–40 minutes and a paid service adds no value. If you have multiple income sources, property income, or you're unsure about expenses and reliefs, a service catches errors and identifies deductions you might miss — for £100–£300, which is often less than the tax you'd overpay by getting something wrong.

Can an online tax return service help if I'm filing late?

Most services can file a late return, and some will advise on penalties. However, if you're behind on multiple years or need to negotiate a Time to Pay arrangement with HMRC, a traditional accountant who knows your full situation is usually better. Online services are designed for current-year filing, not complex historical catch-up work.

What's the difference between a tax return service and accounting software?

Accounting software (like FreeAgent, Xero, or QuickBooks) is a tool you use yourself to track income and expenses and submit returns — you're still doing the work. A tax return service does the work for you: you provide the raw information, and their accountant files the return. Software costs £10–£40/month; a service costs £100–£300 per return. See our [comparison of services vs accountants vs software](/get-help/tax-return-service-vs-accountant-vs-software/) for the full breakdown.

Best Self Assessment Tax Return Services in the UK (2026 Comparison)

If you’ve decided that doing your own Self Assessment is more stress than it’s worth, but you’re not ready to commit to a £500+ traditional accountant, there’s a middle option: online tax return services.

These are platforms where you upload your records, answer some questions, and a qualified accountant files your return with HMRC. They’ve grown rapidly in the UK over the last few years because they fill a genuine gap — cheaper than a high-street accountant, less error-prone than DIY, and faster than either.

This is an independent comparison. We don’t take referral fees from any service listed here, and we haven’t ranked them by who pays the most. The goal is to help you choose based on your actual situation, not a generic “best overall” that means nothing for your specific return.

How Online Tax Return Services Work

All of the services below follow roughly the same process:

You sign up and answer questions about your income sources, expenses, and personal details.
You upload documents — usually bank statements, receipts, P60s, P11Ds, or you connect your bank account directly via Open Banking.
An accountant reviews your information, calculates your tax, and prepares the return.
You review and approve the draft return before it’s submitted.
The service files with HMRC on your behalf, and you receive confirmation.

The difference between services is in price, turnaround speed, what’s included in the base fee, and what triggers an upcharge. That’s what we’re comparing below.

The Main UK Tax Return Services

TaxScouts

TaxScouts is the best-known online tax return service in the UK, built specifically for self-employed people and sole traders.

Price: ~£149 for a sole trader Self Assessment (including one self-employment income source). Additional income sources (property, capital gains, foreign income) cost extra.
Turnaround: Typically 2 working days from submission of all documents.
What’s included: Review by a qualified accountant, filing with HMRC, and a final tax calculation summary. Unlimited messages with your assigned accountant during the process.
What costs extra: Additional income sources, multiple years filed at once, amendment of a previously filed return.
Best for: Sole traders with one or two income sources who want a fast, straightforward filing without ongoing advice. The flat fee and quick turnaround make it the easiest “just get it done” option.
Less suited for: Limited company directors (TaxScouts focuses on Self Assessment, not Corporation Tax), people who need ongoing tax planning, or anyone behind on multiple years.

Untied

Untied positions itself as the budget option for simple returns, with strong banking integration.

Price: From ~£99 for a simple Self Assessment. More complex returns (multiple income sources, property) cost £150–£200.
Turnaround: 1–3 working days depending on complexity.
What’s included: Filing with HMRC, basic expense categorisation, and integration with major UK bank accounts via Open Banking. You can tag transactions in the app and Untied’s accountants use those tags to prepare the return.
What costs extra: Capital gains, foreign income, complex expense claims, multiple years.
Best for: People with very simple returns (one income source, trading allowance or basic expenses) who want the cheapest possible “someone else files it” option. The banking integration is genuinely useful if you already use a business bank account with clean transaction data.
Less suited for: Anyone with capital allowances, complex reliefs, or multiple income streams — the base price assumes simplicity, and the add-ons can push the total above TaxScouts.

Crunch

Crunch is a full-service online accountancy firm, not just a tax return filing service. It’s more expensive but covers more ground.

Price: From ~£300 for a Self Assessment as part of a monthly package (£80–£120/month). Standalone Self Assessment filing is available but less commonly used.
Turnaround: Varies — typically 5–10 working days, faster for existing monthly clients.
What’s included: Self Assessment filing, plus access to Crunch’s accounting software, bookkeeping support, and ongoing advice if you’re on a monthly plan. Limited company accounts and Corporation Tax are included in the higher-tier plans.
What costs extra: Payroll, VAT returns, and complex tax planning are add-ons or higher-tier features.
Best for: Sole traders or limited company directors who want ongoing accounting support, not just a one-off return filing. If you’re going to need help year-round with bookkeeping, MTD quarterly updates, and tax questions, the monthly model makes sense.
Less suited for: Someone who just wants a single return filed quickly and cheaply. The monthly commitment and higher price point are overkill for a one-off filing.

1TapTax

1TapTax is a newer entrant focused on speed and simplicity for straightforward returns.

Price: ~£120–£180 for a sole trader Self Assessment, depending on complexity.
Turnaround: 1–2 working days for simple returns.
What’s included: Filing with HMRC, document upload via mobile app, and review by a qualified accountant.
What costs extra: Additional income sources, capital gains, amendments.
Best for: People who want a fast, app-based experience for a simple return. The mobile upload is convenient if you’re filing from receipts and bank statements on your phone.
Less suited for: Complex returns or anyone who wants ongoing advice. 1TapTax is a filing service, not an advisory relationship.

Quick Comparison Table

Service	Starting price	Turnaround	Best for	Limitations
TaxScouts	~£149	2 days	Sole traders, 1–2 income sources	No limited company, no ongoing advice
Untied	~£99	1–3 days	Simple returns, banking integration	Add-ons for complexity can stack up
Crunch	~£300 (+ monthly)	5–10 days	Ongoing accounting, limited companies	Overkill for one-off simple returns
1TapTax	~£120	1–2 days	Fast app-based simple filing	No advisory, limited to straightforward returns

How to Choose

If your return is genuinely simple

One income source, trading allowance or basic expenses, no property, no foreign income, no capital gains — you don’t need any of these services. Use HMRC’s free online filing. It takes 20–40 minutes, and our first-year self-employed checklist walks you through it.

If you want the peace of mind of someone checking your work but don’t need advice, Untied at ~£99 is the cheapest option.

If you have 2+ income sources

Self-employment plus rental income, or self-employment plus dividends, or any combination that means filling out multiple sections of the return — TaxScouts at ~£149 (plus add-ons) is the sweet spot. The flat-fee structure means you know the cost upfront, and the 2-day turnaround is fast enough to use even in January.

If you have a limited company

You need more than a Self Assessment filing service — you need Corporation Tax, accounts, and likely payroll. Crunch is the only service here that handles the full limited company package. Alternatively, skip the online services entirely and use our find an accountant matching service to get a local firm that specialises in small companies.

If you’re behind on multiple years

None of the online services are designed for this. Filing 3+ years of late returns involves allocating income and losses across tax years, negotiating penalties, and potentially setting up a Time to Pay arrangement. This is traditional accountant territory. Use our find an accountant form and mention you’re behind on returns — we’ll match you with someone who handles catch-up work.

If you want ongoing advice, not just filing

Online services are transactional — you pay per return, and the relationship ends when it’s filed. If you want someone to call when you’re deciding whether to incorporate, whether to claim actual expenses or the trading allowance, or how to handle MTD quarterly updates, you need a traditional accountant on retainer. See our should I hire an accountant guide for when that’s worth it.

What About Accounting Software Instead?

If you’re comfortable doing the return yourself but want help tracking income and expenses through the year, accounting software is a different (and cheaper) option. Software like FreeAgent, Xero, or QuickBooks costs £10–£40/month and handles record-keeping, bank feeds, and — for MTD-compatible tools — quarterly updates. You still file the return yourself, but the software does the number-crunching.

We cover this option in detail in our cloud accounting guide for sole traders and our cheapest MTD software comparison. For the full three-way comparison — software vs online service vs traditional accountant — see our tax return service vs accountant vs software guide.

Ready to Get Help?

If you’ve compared the options and decided you’d rather talk to a real accountant who can handle your specific situation — not just file a return — we can match you with one.

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