When you see GST on an invoice, it is tax on the sale — not an extra fee the seller keeps as profit. The seller collects it and remits it to the tax authority according to local rules.

This page is about reading and writing the GST line on an invoice. For how GST compares to VAT and US sales tax, see GST vs VAT vs sales tax.

What the GST line is telling you

On a typical tax invoice you will see:

  • A subtotal (amount before GST)
  • A GST amount (often with the rate, e.g. 10%)
  • A total (what the buyer pays including GST)
  • Often a GST registration number (ABN, GSTIN, BN, etc.)

If GST is missing where it is required, the document may not count as a valid tax invoice for the buyer’s records.

Quick example (Australia, 10% GST)

Service fee before tax: $500.00 GST (10%): $50.00 Total: $550.00

The client pays $550. The seller later remits the $50 GST (subject to their filing rules and any credits they can claim).

What you should put on your own invoice

If you are registered (or required) to charge GST:

  1. Show prices clearly as GST-exclusive or GST-inclusive — pick one approach and stay consistent.
  2. Display GST as its own line (or a clearly labeled tax total).
  3. Include your registration number where local rules require it.
  4. Make sure the total the client owes matches subtotal + GST (minus any discounts).

Common mistakes

  • Hiding GST inside a single “total” with no breakdown — many buyers need the GST amount shown separately.
  • Charging GST when you are not meant to (or skipping it when you must) — rules and thresholds differ by country; check local guidance.
  • Forgetting the registration number on invoices that need it for tax validity.
  • Mixing inclusive and exclusive pricing on the same document so the math no longer makes sense.