Seven invoice mistakes worth checking before you send

1–2. Wrong tax basis or tax treatment

Adding GST twice: if a unit price already includes GST, choose the inclusive setting. A $110 inclusive item should finish at $110, containing $10 GST. Selecting exclusive would incorrectly make it $121.

Taxing every line: a registered business may have GST-free or input-taxed sales. Check each item. A $100 taxable item and $50 GST-free item give $10 GST, not $15.

3–4. Wrong quantity or unclear description

Invalid quantity: a blank, negative or zero quantity should not silently become one. The maker flags these entries and blocks printing until the issue is resolved. For 2.5 hours at $80, the extended price before GST is $200.

Vague description: “services” may leave the customer unsure what they received. Identify the work, product or billing period, and use the quantity field where appropriate. Descriptions also help you recognise the transaction months later.

5–6. Wrong identity or missing buyer information

Mistyped ABN: use the format check, then confirm the business in official ABN Lookup. A checksum result is not identity verification. Never copy an ABN from another business to make a form pass.

Missing buyer: for an ordinary tax invoice totalling $1,000 or more, identify the buyer or include their ABN. Customer details are useful below that amount too, particularly for resolving payment queries.

7. Sending an unchecked payment instruction

Read the payment terms and bank details character by character. Compare them with your own trusted records. If payment instructions have changed, communicate that change through a channel your customer already knows.

Finally, review the PDF preview, confirm the invoice number and date, and save a copy outside the browser. The local draft is a convenience, not a backup system: clearing browser storage or using a different device will not preserve it.

Common questions