How to write a proper NZ tax invoice

For most contractors the invoice is the only document a client ever scrutinises, and the one Inland Revenue cares about when GST claims are checked. What an invoice legally requires is a short list, and once your template has it, every invoice after that is automatically right. This guide covers what must be on it, what changed in 2023, and the practices that get you paid faster.

"Tax invoice" rules became taxable supply information

Since 1 April 2023, the law no longer requires a document called a tax invoice. Instead, GST-registered sellers must provide and keep taxable supply information: a minimum set of facts about each sale. You can still send a document headed "Tax invoice", and most contractors do, but it's the information that matters now, not the label.

What your invoices must include

The required fields step up with the size of the sale. For a contractor, almost every invoice will be in the top tier, over $1,000, so if you build the template for that, every smaller invoice is covered too:

• Your name (or trade name) and your GST number.
• The date of the invoice or the time of supply.
• A description of the goods or services.
• The amounts: either the GST-exclusive amount, the GST, and the GST-inclusive total shown separately, or a GST-inclusive amount with a statement that it includes GST at the standard rate.
• For sales over $1,000 to a GST-registered buyer: the buyer's name plus at least one identifier, such as their address, phone number, email, trading name, NZBN, or website.

Smaller sales need less. A sale of $200 or less needs only your name, the date, a description, and the amount. There is no downside to providing the full set every time.

What the law doesn't require but clients do

The legal list gets you compliant. These next few things get you paid:

• An invoice number. This is not legally required, but it is essential for your records, which must be kept for seven years, for your client's accounts-payable process, and for any later conversation about which invoice is outstanding. Keep them sequential, with no gaps, and use one numbering scheme.
• A due date and payment terms. An invoice without a due date reads as optional. State the date, and the terms it came from, such as 7 days, 14 days, or the 20th of the following month.
• Your bank account number, shown clearly. Every extra step the client's accounts person has to take to find it can add a day to how long you wait to be paid.
• A purchase order or reference number when the client uses them. Large organisations pay against purchase orders, and an invoice without one can sit unmatched in a queue for weeks.
• Line items that match the agreement. Break the work down the way the client agreed to buy it, whether that is by days, milestones, or deliverables, so approval doesn't need a conversation.

The mistakes that delay payment

• Charging GST while unregistered, or forgetting to add it once registered.
• Showing amounts without stating whether GST is included.
• Reusing or skipping invoice numbers, which can make your records look disorganised.
• Sending the invoice to the person who hired you instead of the address their accounts team actually processes.

How Coffer helps

Coffer fills in the required fields on every invoice for you: your business details and GST number from your profile, a sequential invoice number, per-line amounts with the GST worked out and shown, due dates from your default terms, and your bank account in the footer. You can switch GST off per invoice for work that shouldn't carry it. Every invoice is stored as a PDF, so you keep the seven-year record without extra work.