Registering as self-employed or a sole trader: what the tax and business pages say, five countries

This page reports what the official source says. It is not legal advice: ask the office named here. It describes registration pages only. Whether a worker counts as self-employed or as an employee is a separate question that each office answers under its own tests, and the guide on cover when subcontracting points to those.

United States

The Internal Revenue Service (IRS) self-employed individuals tax center says a person is generally self-employed if they run a trade or business as a sole proprietor or independent contractor, belong to a partnership that runs one, or are otherwise in business for themselves, including part-time or as a gig worker. It says a self-employed individual generally files an annual income tax return and pays estimated tax every quarter, and generally pays self-employment tax, which it describes as a Social Security and Medicare tax. It says a return is due where net earnings from self-employment were US$400 or more. It names Schedule C for reporting income or loss from a sole proprietorship.

The page does not describe a registration step for a sole proprietor. A separate IRS page covers the Employer Identification Number (EIN). It says an EIN can be obtained directly from the IRS online, for free, and issued immediately if the application is approved. It warns that some websites charge for an EIN and says an EIN never has a fee. It says the online tool is for a domestic organization formed in the United States or its territories, with its principal place of business there, and needs the responsible party's Social Security number or individual taxpayer ID number.

United Kingdom

The GOV.UK page on registering for Self Assessment as self-employed says a person tells HM Revenue and Customs (HMRC) by October 5, 2026 if they need to complete a tax return for the tax year that ended April 5, 2026 and either have not sent a return before or registered before but did not need to send a return for 2024 to 2025. It says telling HMRC after October 5, 2026 could bring a penalty. It also refers to a Unique Taxpayer Reference (UTR) for people waiting for a reply from HMRC.

The same site describes the Construction Industry Scheme (CIS). Under it, contractors deduct money from a subcontractor's payments and pass it to HMRC, and the deductions count as advance payments towards the subcontractor's tax and National Insurance. GOV.UK says contractors must register for the scheme, subcontractors do not have to register, and deductions are taken at a higher rate from subcontractors who are not registered. It lists construction work the scheme covers, such as work on a permanent or temporary building or structure and civil engineering work. The page does not name tree work either way, so whether a given job is covered is a question for HMRC. The GOV.UK passages in this section are adapted under the Open Government Licence v3.0.

Australia

business.gov.au says an Australian business number (ABN) is an 11-digit number, unique to a business, that identifies it to government, other businesses and the public, and does not replace a tax file number. It lists uses, including avoiding pay as you go (PAYG) tax on payments received and claiming goods and services tax (GST) credits. It says registering is free through the Australian Business Register, which the Australian Taxation Office manages, and that not everyone needs an ABN: one is for a person running a business or other enterprise.

On the process, the page says an applicant needs their business structure, proof of identity and details of business activities and associates. It says a successful online application gives the ABN straight away, an unsuccessful one gives a refusal number with a letter within 14 days, and one needing review gives a reference number, with reviews taking up to 20 business days. It says details must be updated within 28 days of becoming aware of a change, and that moving from sole trader to a company or a partnership needs the ABN cancelled.

Canada

The Canada Revenue Agency (CRA) page on registering a business describes how to register for a business number (BN) and CRA program accounts. It gives two routes: one for Canadian residents with a valid Social Insurance Number, which includes people with a temporary number starting with 9, and one for non-residents doing business in Canada. The page does not describe which accounts a sole proprietor needs. It links to a separate page called "Program accounts you may need". Its details carry the date November 28, 2025.

New Zealand

The business.govt.nz page on registering with government agencies says sole traders, partnerships and trusts can register for a New Zealand Business Number (NZBN) for free on the NZBN website. It lists three things needed: a RealMe login, an IRD number for the sole trader, partnership or trust, and basic details that vary by structure. It says a company that registers gets an NZBN automatically. The page also describes myIR, the Inland Revenue online account, as the place to keep personal and business details up to date and to file business returns including employer returns and GST.

At a glance

Country	Registration the page names	Number
United States	No step named for a sole proprietor; EIN page separate	EIN, free
United Kingdom	Self Assessment; CIS for subcontractors	UTR
Australia	ABN through the Australian Business Register, free	11-digit ABN
Canada	Business number and program accounts	BN
New Zealand	NZBN, free; myIR account	NZBN and IRD number

For the other registrations that starting a business involves, see the guide on starting a tree service by country.