Claiming GST credits is easy to do and easy to get wrong. The entry goes on your activity statement in a few minutes; the evidence behind it has to hold up later, often two or three years after the purchase, when nobody in the business remembers the job, the supplier or the reason. This guide covers what the Australian Taxation Office (ATO) says about when you can claim, the records that substantiate a claim, the gaps that most often cause credits to be denied, and how to keep your paperwork review-ready.
Start with entitlement, not paperwork
Records cannot fix a claim you were never entitled to make. According to the ATO's guidance on when you can claim a GST credit, the starting point is registration: you can claim GST credits if you are registered for GST. If you are not registered, there is nothing to claim, no matter how good the invoices are.
The ATO's page also deals with two other points that shape the record-keeping job:
- The tax period you claim in. The ATO sets out which tax period a credit belongs to. Where the rules allow you to claim in a later BAS than the one you first thought applied, the ATO is explicit: you will need to keep your own records that document and evidence your choice to claim the GST credits in that later BAS. In other words, the election itself is a record you must create and keep, not just a decision you make in your head.
- Refunds. If your GST credits are greater than the amount you are liable to pay, the ATO states you are entitled to a refund. That makes substantiation more important, not less: a refund position is the one most likely to draw questions.
If you are a non-resident business selling goods and services into Australia, the ATO points to separate guidance for non-resident businesses. Do not assume the domestic rules apply unchanged to your situation.
The four layers of evidence behind one credit
Think of each credit as needing four separate things to line up. Most reviews fail on one layer, not all four.
1. A document from the supplier. A tax invoice is the backbone of a credit claim. The ATO publishes the current list of what a tax invoice must contain, and you should check your documents against that list rather than against habit. Where a document does not meet the tax invoice requirements, the credit is at risk even if the purchase was genuine and paid for.
2. Proof you actually paid. Bank statements, card records, BPAY references or a remittance advice connect the invoice to money leaving the business. This matters where suppliers reissue documents, where invoices are paid from a personal account, or where a director reimburses the business later.
3. A business-purpose link. A credit claim is about a purchase made for your business. Where an item has mixed private and business use, the gap is rarely the invoice — it is the missing note explaining the split and how you arrived at it. Write it down at the time, while you still know.
4. BAS working papers. Your accounting system should reconcile to what was lodged. Keep the period's reports, the reconciliation between total purchases and total credits claimed, and any adjustments made. If the ATO asks how a BAS figure was built, the working paper is the answer.
Where claims usually fall over
- Missing or incomplete supplier documents. Credits claimed from statements, order confirmations or quotes instead of a compliant tax invoice.
- Wrong entity or wrong name. Trading names, old company names and related entities get mixed up on invoices. The document should match the entity that is registered and claiming.
- The purchase sits in the wrong period. Credits claimed early, claimed twice across periods, or claimed long after the purchase without any record of why the later period was chosen.
- Mixed-use items with no split recorded. Vehicles, phones, internet, home office costs and travel are the usual suspects.
- Purchases that are not creditable at all. Some acquisitions are excluded even with a perfect invoice. Check the ATO's current guidance on what you cannot claim before lodging, rather than after a review starts.
- Supplies from overseas or inbound arrangements. Where a non-resident supplier or an inbound supply is involved, the analysis can differ. The ATO directs non-resident businesses selling into Australia to separate guidance.
Checklist: is this credit ready to claim?
| Check | What "ready" looks like |
|---|---|
| Registered for GST at the time | Registration covers the period the purchase was made |
| Supplier document held | Document present and checked against the ATO's current tax invoice requirements |
| Payment evidenced | Bank or card record matching the supplier and amount |
| Business purpose recorded | Note explaining why the business bought it, and any private-use split |
| Correct tax period | Credit sits in the period the ATO's rules allow, with a written record if a later BAS was chosen |
| Reconciled to the BAS | Working papers tie the claimed figure back to purchase records |
| Retention | Stored where it can be retrieved years later, in a readable format |
Choosing the right tax period
The tax period question deserves separate attention because it generates both under-claims and disputes. The ATO's guidance covers which tax period you can claim GST credits in, and it specifically contemplates claiming in a later BAS in some circumstances — with the condition that you keep your own records documenting and evidencing that choice.
Practical interpretation: if you realise a purchase was missed, do not simply drop it into the current period and move on. Confirm the treatment the ATO allows, and if you are claiming in a later BAS, create a short file note at the time — what the purchase was, which period it originally belonged to, and why it is being claimed now. That note is the record the ATO refers to.
If the ATO asks questions
A review is usually a document request, not an accusation. Expect to produce the supplier document, proof of payment and the business-purpose explanation for sampled transactions. Being able to retrieve those quickly changes the experience. If your records are scattered across email inboxes, a phone camera roll and a shoebox, fixing retrieval now is worth more than any other single improvement.
Two habits help: store documents against the transaction rather than in folders by supplier, and run a short monthly check that new purchases have a compliant document attached before the period is lodged. Corrections are far easier before lodgement than after.
Things to verify before you rely on this
Because details change, confirm the following against the ATO website or with your registered tax agent:
- The current conditions for when you can claim a GST credit, and any acquisitions that are excluded.
- What a tax invoice must contain today, and the circumstances where a different document is acceptable.
- Which tax period your credit belongs to, and whether a later-BAS claim applies to you.
- How long you must keep records, and in what form.
- Whether any rule specific to your industry, entity type or residency status changes the answer.
Next steps
- Open the ATO's "When you can claim a GST credit" page and confirm you meet each condition for the period you are about to lodge.
- Run one quarter of purchases through the checklist above and count how many have all four evidence layers. That gives you a baseline.
- Fix retrieval before you fix anything else — one location, documents attached to transactions, monthly check before lodgement.
- For any missed purchase, record the period decision in writing before you claim it.
- Where the amounts are material, or where you are unsure about apportionment, residency or exclusions, put the question to a registered tax agent rather than guessing.
General information only. This article is general information about Australian GST record-keeping and is not advice about your circumstances, and it is not tax, legal or financial advice. Rules and ATO administrative approaches change. Check the current position with the ATO or a registered tax agent before acting. Australian Ltd is not the ATO, a regulator or a tax adviser, and does not prepare or lodge activity statements.