VAT and self-assessment for UK affiliate publishers explained

What to take away

• UK affiliate publisher VAT self-assessment starts with registering for self-assessment once commission income exceeds £1,000 a year, then reporting it on an SA100 with the SA103 self-employment pages.
• HMRC treats affiliate commission as trading income, not hobby income, so it is taxable whether or not you receive a form from a network.
• You must register for VAT once your rolling 12-month taxable turnover passes £90,000, and MTD for VAT requires digital records and compatible software.
• Filing and payment deadlines are 31 January for online returns, with payments on account due on 31 January and 31 July.
• Cross-border work with EU networks can create VAT and distance-selling obligations, especially for goods shipped from Northern Ireland.

How HMRC treats affiliate commission as taxable income

HMRC is the UK tax authority, and it sees affiliate commission as money earned from a trade. You are not employed by the network or the merchant. You are a sole trader or a company providing a service: sending traffic, leads or sales in return for a cut.

That distinction matters. Employment income is taxed through PAYE. Affiliate commission is taxed as trading profit, which means you report income and deduct allowable expenses. The profit left over is what HMRC taxes.

If you earn commission as an individual, HMRC normally expects you to register for self-assessment once your gross income from self-employment is more than £1,000 in a tax year. The £1,000 trading allowance can cover very small operations, but it does not cover VAT or every situation.

Affiliate income is not a capital gain, and it is not a gift. It is revenue. A single payment from an affiliate network can include commissions from several merchants, and you still report the total you receive.

What counts as affiliate commission

Commission includes flat fees per lead, percentage cuts of sales, bonus payments for hitting targets, and recurring commissions from subscriptions. It also includes payments in kind if a network pays you in credit or goods rather than cash.

Some publishers earn through ad networks, sponsored posts or display advertising. Those are usually separate income streams, but HMRC looks at the whole picture. If the activity is commercial and repeated, it is taxable.

You should keep records of every payment, including the network statement, the payment date and any tax withheld. If a network deducts tax before paying you, that deduction may count towards your tax bill, but you need the paperwork.

Allowable expenses for affiliate publishers

You can deduct costs that are wholly and exclusively for the trade. Typical examples include web hosting, domain names, software subscriptions, affiliate network fees, advertising spend, and a proportion of home broadband and electricity if you work from home.

You cannot deduct personal spending. You also cannot deduct the full cost of a laptop if you use it mainly for personal use, though you can claim the business proportion. Capital allowances may apply for larger equipment.

A simple spreadsheet works at the start. As income grows, accounting software reduces the risk of missing a deduction. The affiliate marketing costs article explains how to separate business and personal spending without overcomplicating it.

Sole trader or limited company

Most UK affiliate publishers start as sole traders. You are the business, and you report profit on your personal tax return. It is simple and cheap to run, but you are personally liable for debts and tax.

A limited company is separate. The company pays corporation tax on profits, and you take a salary or dividends. It can be more tax-efficient at higher profit levels, but it brings filing duties at Companies House and stricter record-keeping.

There is no single right answer. The choice depends on profit, risk and how you want to take money out. If you are unsure, an accountant who knows affiliate marketing is worth the fee.

Self-assessment registration and the SA100 and SA103 forms

Self-assessment is HMRC's system for reporting income that is not taxed through PAYE. You register once, file a return each year, and pay what you owe.

The main form is the SA100, the core self-assessment tax return. If you are a sole trader, you also complete the SA103 self-employment pages. The SA103 is where you put your turnover, expenses and profit.

If you have other income, such as dividends, rental income or foreign income, you may need extra pages. Affiliate publishers with a limited company do not usually file an SA103 for the company. The company files its own accounts and corporation tax return.

Registering with HMRC

1. Create a Government Gateway account if you do not already have one.
2. Register for self-assessment as a sole trader, using your National Insurance number and business details.
3. Wait for your Unique Taxpayer Reference, usually within 10 working days if you register online.
4. Use the UTR to file your return and to set up a payment method.
5. Keep your Government Gateway details safe, because you will need them every year.

If you are new to self-assessment, register by 5 October after the end of the tax year in which you started trading. That deadline is easy to miss when affiliate income arrives in small amounts.

Filling in the SA103

The SA103 asks for your business name, description and accounting date. You then enter turnover, expenses and net profit. Turnover is your gross commission before fees and costs.

Expenses go in the relevant boxes. There are boxes for premises, travel, office costs and professional fees. If you use the cash basis, you record money when it comes in and goes out, which suits most small publishers.

The form also asks whether you used the trading allowance. If you did, you cannot deduct expenses as well. You choose one or the other, so compare the numbers before deciding.

Records you need to keep

HMRC expects records of all sales and expenses for at least five years after the 31 January filing deadline. That includes network statements, bank statements, invoices and receipts.

Digital records are fine. What matters is that you can show where each figure came from. If HMRC asks questions, a clear trail saves time and stress.

For a fuller picture of what running an affiliate business costs, including platform fees and software, see the guide to affiliate marketing costs and pricing.

When affiliate income crosses the VAT registration threshold

VAT is a tax on most goods and services. The VAT registration threshold in the UK is £90,000 of taxable turnover in any rolling 12-month period. Once you go over it, you must register.

Rolling means you look back at the previous 12 months, not the calendar year or your accounting year. If your commission total passes £90,000 in that window, you have 30 days to tell HMRC, and registration usually starts from the first day of the second month after you exceeded it.

You can also register voluntarily below the threshold. That can make sense if you want to reclaim input VAT on software, equipment or advertising. It can also help if you work mainly with VAT-registered businesses.

The downside is administration. You must charge VAT on your supplies, file returns and keep digital records. For publishers selling to consumers, voluntary registration can make your prices less competitive.

What VAT registration means for your business

Once registered, you add VAT to your invoices unless the supply is exempt or outside the scope. You reclaim VAT on business purchases. You file VAT returns, usually quarterly, and pay the difference.

You also need to show your VAT number on invoices and keep proper records. The government's guidance on what registering for VAT may mean for your business sets out the main obligations.

If you sell to other businesses, they may not care about the extra VAT because they reclaim it. If you sell to consumers, the VAT comes out of your margin unless you raise prices.

Affiliate commission VAT treatment

This is where affiliate publishing gets tricky. The VAT treatment depends on what you actually supply. If you are an intermediary connecting a merchant with a customer, your supply may be a service to the merchant or network.

If you are a publisher selling advertising space, that is usually a standard-rated supply. If you are promoting goods and earning a commission, the nature of the service matters. Some supplies are exempt, especially in financial services.

HMRC's VAT guidance is the starting point, but the detail depends on your contracts. Read what the network says you are providing, and check whether VAT is added to your commission.

Invoicing and VAT on commission

If you are VAT-registered, you normally charge VAT on your commission unless the service is exempt. Some networks pay commission gross and expect you to account for VAT. Others add VAT at source.

You need to know which model applies. If you charge VAT and the network does not pay it, you still owe it to HMRC. That can wipe out a thin margin, so check before you sign up.

Keep invoices for every commission payment. If the network is overseas, the place of supply rules may shift the VAT obligation. That is covered in the cross-border section below.

VAT rates, exemptions and partial exemption for mixed affiliate supplies

Most affiliate services are standard-rated at 20%. Some are reduced-rated at 5%, and some are zero-rated. A few are exempt. The rate depends on the service, not on your job title.

If you only make standard-rated supplies, life is simple. You charge 20%, reclaim input VAT, and pay the difference. If you make exempt supplies too, you may be partially exempt, which limits how much input VAT you can reclaim.

Partial exemption is common for publishers with mixed income. Display advertising may be standard-rated, while some financial promotions are exempt. You then have to work out how much VAT you can recover.

Standard, reduced and zero rates

Supply type	Typical VAT treatment	What it means for you
Display advertising	Standard rate, 20%	Charge VAT, reclaim input VAT
Affiliate lead generation	Usually standard rate	Check the contract and network terms
Financial promotions	Often exempt	May limit input VAT recovery
Digital publications	Standard rate	VAT applies to most digital content
Printed books and newspapers	Zero rate	Rare for affiliate publishers

This table is a guide, not a ruling. The exact treatment depends on your agreements and on HMRC's view of the supply. If the amounts are large, get advice.

Partial exemption basics

Partial exemption applies when you make both taxable and exempt supplies. You cannot reclaim all the VAT on your costs. You work out a recoverable proportion, usually based on turnover.

There is a de minimis rule. If your exempt input VAT is below a set amount and below a proportion of your total input VAT, you can usually reclaim it all. The figures change, so check current HMRC guidance.

You can also use a special method approved by HMRC if the standard method gives a distorted result. That is more common for larger publishers with complex income streams.

The government's guidance on exemption and partial exemption from VAT explains the calculations and the records you need.

Keeping mixed supplies clean

Separate your income streams in your accounts. Label display advertising, affiliate commission, sponsored content and any other revenue. That makes the partial exemption calculation easier.

If you use one bank account for everything, you can still separate income in your bookkeeping. The key is consistency. HMRC wants to see a clear method, not a perfect one.

Review your position each year. A change in the mix of income can change how much VAT you can reclaim. Small publishers often drift into partial exemption without noticing.

Making Tax Digital for VAT and digital record-keeping duties

Making Tax Digital for VAT, usually shortened to MTD for VAT, requires VAT-registered businesses to keep digital records and file VAT returns using compatible software. Spreadsheets alone are not enough unless they are linked to filing software.

MTD for VAT applies to all VAT-registered businesses, including sole traders. There is no turnover threshold for MTD for VAT now. If you are registered for VAT, you are in scope.

The rules cover the records you must keep and the way you send returns. You cannot just type figures into the HMRC website for a VAT return. You need software or an API-enabled spreadsheet.

What digital records mean

You must keep records of your sales and purchases digitally. That includes the time of supply, the value, the VAT rate and the VAT amount. You also need records of your VAT account and any adjustments.

Digital links are required between your records and your return. That means no manual copying of totals from one system to another. Some small businesses use bridging software to connect spreadsheets to HMRC.

The Making Tax Digital for VAT collection sets out the detailed requirements and the list of compatible software.

Software choices for small publishers

Accounting software ranges from free starter plans to full bookkeeping suites. Most UK packages handle MTD for VAT filing. Some affiliate networks provide statements you can import as CSV files.

If you already use spreadsheets, check whether your software supports digital links. A spreadsheet plus bridging software can work, but it needs discipline. One missed link can break the digital chain.

Costs vary. A simple MTD-compatible package may cost a few pounds a month, while a full suite costs more. Treat it as a business expense. The affiliate marketing budget template can help you plan for software and accountancy fees.

Common MTD mistakes

• Filing a VAT return without digital links between records and the return
• Using a spreadsheet that is not connected to filing software
• Keeping paper receipts with no digital record of the amounts
• Forgetting to record the VAT rate on each sale
• Missing the quarterly deadline because the software was not set up in time

Deadlines, payments on account and penalties for British publishers

Self-assessment deadlines are fixed. The tax year runs from 6 April to 5 April. If you file online, the return is due by 31 January after the tax year ends.

Paper returns are due by 31 October, but most publishers file online. The 31 January deadline also applies to the tax payment. If you file late, penalties start immediately.

Payments on account are advance payments towards your next tax bill. HMRC asks for two each year, on 31 January and 31 July. Each is usually half of your previous year's tax bill.

If your income is uneven, you can ask HMRC to reduce your payments on account. You must have a good reason, and you cannot reduce them below what you actually owe.

Key dates table

Date	What is due
5 October	Register for self-assessment if you started trading in the previous tax year
31 October	Paper self-assessment return deadline
31 January	Online return and balancing payment deadline
31 January	First payment on account for the next tax year
31 July	Second payment on account

VAT returns are usually quarterly. The deadline is one month and seven days after the end of the VAT period. Payments must clear by the same date.

Penalties and interest

Late filing triggers an automatic £100 penalty, even if you owe no tax. If it continues for three, six and twelve months, further penalties will be imposed. Late payment interest runs daily.

HMRC can also charge penalties for careless or deliberate errors. If you spot a mistake, correct it quickly. Voluntary disclosure usually leads to lower penalties than an HMRC investigation.

If you cannot pay, contact HMRC before the deadline. Time to pay arrangements are possible, but they are not automatic. Ignoring the problem makes it worse.

Planning for the tax bill

Set aside a percentage of each commission payment. Many publishers put 20% to 30% aside, depending on their tax band. That avoids a scramble in January.

Keep your business and personal money separate. A separate bank account makes the tax calculation easier and reduces the risk of spending money you owe. Review your affiliate marketing hidden costs so your tax planning includes the full picture.

Cross-border VAT issues for UK publishers working with EU networks

Many UK affiliate publishers earn from EU-based networks and merchants. Cross-border work brings extra VAT questions, especially after Brexit.

If you are VAT-registered in the UK, the place of supply rules decide where VAT is due. For business-to-business services, the reverse charge often applies, meaning the EU customer accounts for VAT.

You need to check whether your contract is with the network or the merchant, and where they are established. That determines your invoicing and reporting duties.

B2B services and the reverse charge

Most affiliate services to EU businesses fall under the general rule for business-to-business services. The place of supply is where the customer belongs, so the customer accounts for VAT under the reverse charge.

You still need to report the sale on your VAT return, usually as a zero-rated or outside-the-scope supply. You should also keep evidence of the customer's VAT number and business status.

If the network is outside the EU, different rules may apply. The principle is similar, but the reporting boxes on your return can differ.

Distance sales from Northern Ireland

Northern Ireland has special rules because of the Windsor Framework. If you sell goods to consumers in the EU from Northern Ireland, you may be affected by distance-selling rules.

The government's guidance on VAT on distance sales of goods from Northern Ireland to the EU explains when you must register and account for VAT in an EU country.

Most affiliate publishers sell services, not goods. But if you also sell physical products, or if you promote goods under a model where you are the seller, this can apply.

Records for cross-border work

Keep evidence of every cross-border transaction. That includes invoices, contracts, proof of customer location and VAT numbers. HMRC expects you to show why you treated a supply as outside the scope or zero-rated.

If you use an EU network that pays you without VAT, check the contract. Some networks handle VAT for you, and some do not. The difference can be significant.

Exchange rates matter too. Convert foreign currency income using a consistent method, such as HMRC's monthly exchange rates or the rate on the transaction date. Record the method you use.

Common questions

Do I need to register for self-assessment if I only earn a small amount from affiliate links? If your gross self-employment income is more than £1,000 in a tax year, HMRC normally expects you to register. Below that, the trading allowance may cover it, but you should still check your overall position.

What is the VAT registration threshold for UK affiliate publishers? The threshold is £90,000 of taxable turnover in any rolling 12-month period. Once you exceed it, you must register within 30 days and account for VAT from the appropriate date.

Which self-assessment forms do I need as a sole trader affiliate publisher? You complete the SA100 tax return and the SA103 self-employment pages. The SA103 is where you report turnover, expenses and profit from affiliate commission.

Does Making Tax Digital for VAT apply to me if I am a sole trader? Yes. MTD for VAT applies to all VAT-registered businesses, including sole traders. You must keep digital records and file returns using compatible software.

When are self-assessment and VAT payments due? Self-assessment online returns and balancing payments are due by 31 January, with payments on account on 31 January and 31 July. VAT is usually due one month and seven days after the end of each VAT period.

How is affiliate commission treated for VAT? It depends on the supply. Many affiliate services are standard-rated at 20%, but some financial promotions are exempt. Check your contracts and HMRC guidance before deciding.