Self Assessment is one of the systems HM Revenue & Customs (HMRC) uses to collect tax through income. Many people have tax deducted automatically through Pay As You Earn (PAYE), but you may have to complete a tax return if you receive other income that has not already been taxed, including income from breeding and selling dogs.
We understand the process can feel daunting, especially for new breeders, but this page is designed to support you by bringing together key links and guidance. Here you’ll learn what Self Assessment is, who needs to register for it, important deadlines, and how to complete your return online. You can also watch the New to Self Assessment webinar for step-by-step visual guidance.
You can check to see if you need to complete a tax return on the Government website.
Key things to know
- The UK tax year runs from 6 April to 5 April.
- You must register for Self Assessment if you earn more than £1,000 before any expenses from breeding and selling dogs in a tax year, regardless of whether this is a one-off or regular activity. This includes stud dog owners, that are receiving income via stud dog fees.
Registering for your Self Assessment
You’ll need to register for Self Assessment by 5 October following the end of the tax year in which you earned the income.
To register:
- Visit the HMRC Self Assessment registration page.
- Select ‘self-employed’ from the options. Dog breeders should register as self-employed for Self Assessment purposes. This is the correct classification for reporting trading income such as selling puppies, even if you have a job in which you already pay tax.
- Provide your personal details, including your National Insurance number, and describe your activity (e.g. “occasional dog breeding and sales”).
- HMRC will send you a Unique Taxpayer Reference (UTR) and instructions to set up your online account. Your UTR will arrive by post within 15 days (or 21 days if abroad). You may also be able to find it in your HMRC online account or the HMRC app. Keep it safe as you’ll need it to submit your tax return.
If you’ve registered for Self Assessment before, you don’t need to register again, but if you didn’t submit a return in the previous year, you’ll need to reactivate your Self Assessment account.
Completing your tax return
The online tax return and payment deadline is 31 January.
You can start your online return as soon as you receive your UTR and activate your online account. You will need records of your income, expenses, receipts, and any tax already paid.
To complete your tax return, log in at GOV.UK. Please be aware, HMRC works out your total tax based on your overall income for the year. Therefore, if you are also employed, enter the tax deducted through PAYE by your employer - if you don’t, your tax bill will be higher than you expect.
Did you know there are allowable expenses?
If you earn money from breeding dogs, you may be able to deduct certain allowable expenses from your taxable income, including:
- Activities e.g. sport and showing expenses (including travel costs, show entries, accommodation, grooming equipment etc.)
- Advertising and promotion costs (including website costs and puppy adverts etc.)
- Breeding equipment (including whelping box, heat lamps, vet bedding, vet scans, cleaning supplies, cameras used to check on puppies etc.)
- Cleaning and hygiene supplies, as well as dog waste disposal costs
- Dog owning equipment (including crates, bowls etc.)
- Dog walker/ sitter/ groomer fees
- Educational courses or materials relating to breeding or dog care
- Food for the dam and puppies
- Health testing
- Home expenses (including proportion of heating, electricity, water etc.)
- Pet insurance costs
- Royal Kennel Club fees (including registration for puppies, Kennel Name maintenance, Find a Puppy adverts etc.).
- Stud fees
- Transport costs (including vet trips, stud visits etc.)
- Veterinary costs (including consultation fees, parasitic treatments, vaccinations, microchipping, c-section etc.)
Keep receipts for all expenses! For more information on record keeping, visit: Business records if you're self-employed: Overview - GOV.UK
Self Assessment - Record Keeping Template
Top Tips
- Stay organised: To save time and stress, keep an up-to-date spreadsheet or use software compatible with Making Tax Digital for Income Tax. To help you, you can download our example template for tracking income and expenses here: LINK. The self-employed who earn over £50,000 will need to report using Making Tax Digital from April 2026: Find out if and when you need to use Making Tax Digital for Income Tax - GOV.UK
- Submit early: Completing your return as soon as possible gives you time to check it’s all correct and gives you up to 10 months to pay your bill. It prevents last minute surprises.
Useful quick links
You can find full guidance on GOV.UK, including:
- How to register
- How to file your return
- How to pay your bill
- Refunds and penalties
- Help and support
HMRC also provides video guidance on YouTube and help sheets for self-employed taxpayers, such as dog breeders.
Download the HMRC app to find your National Insurance number, view your employment and income history from the past five years and more. Download today from the App Store or Google Play.
Still need help?
If you need extra support, you can contact HMRC via Self-Assessment: general enquiries - GOV.UK.
Some breeders find the process daunting so if you still don’t feel confident you could consider some professional support: Find a bookkeeper to do accounts and tax returns.