Do I need a separate IRD number?

No as a sole trader, you use your personal IRD number for your business. You don't need to apply for a separate business IRD number.

Why your personal IRD number is enough

As a sole trader, you and your business are the same legal entity. All your business income is reported through your personal income tax return (IR3), and all tax is paid under your personal IRD number. There's no need for a separate identifier.

This is different from a company, which is a separate legal entity and must have its own IRD number.

When would you apply for a business IRD number?

A separate business or organisation IRD number is required for:

Limited liability companies (Ltd)
Partnerships
Trusts
Clubs and incorporated societies

If you're operating purely as a sole trader, none of these apply.

What if you don't have an IRD number at all?

If you don't yet have a personal IRD number, you'll need to apply for one before you can start working for yourself and paying tax. You can apply:

Online through myIR at ird.govt.nz
By post using the IR595 form (IRD number application — resident individual)

You'll need to provide proof of identity (passport or NZ driver licence) and proof of address.

Do you need to notify IRD when you start trading?

Yes — while there's no formal "sole trader registration", you do need to let IRD know you've started working for yourself. Here's how:

Log in to myIR at ird.govt.nz
Click the 'I want to…' tab
Select 'Send a message'
Choose 'This message is not relevant to a specific account'
Under message category, select 'Other'
In the subject line, type: 'Notification to become a sole trader'

IRD will update your file and you'll be set up to file IR3 returns from then on.

Should you get an NZBN?

An NZBN (New Zealand Business Number) is a unique 13-digit identifier that any NZ business can have. While it's not required for sole traders, having one can make it easier to deal with suppliers, clients, and government agencies.

You can register for a free NZBN at nzbn.govt.nz.