BAS workflow: from Karven to the ATO portal

This article picks up where BAS pre-fill leaves off. Pre-fill produces the numbers; this article is about the operational quarterly loop, what to check, when, and how the final lodgement happens through the ATO portal.

The four-week cadence

For a quarterly BAS lodger, the rough cadence each quarter looks like this:

| Week | What you do | | --- | --- | | Week 0 (last week of quarter) | Make sure all invoices are sent. Chase outstanding accepted quotes that haven't been invoiced yet. | | Week 1 | Reconcile the bank against Karven. Resolve any unmatched payments. | | Week 2 | Generate the BAS pre-fill. Review each line. Add manual adjustments. | | Week 3 | Share with your bookkeeper if you use one. Apply their feedback. | | Week 4 | Lodge through the ATO portal. Pay any GST owing. |

Quarterly BAS is due by the 28th of the month following quarter end (so Q1 / Jul-Sep is due 28 Oct, etc.). Karven puts a banner on the dashboard 14 days before the due date.

Step 1: Close out invoicing

Before you generate the BAS, make sure every job that should be billed for the quarter actually has been. Karven shows you a "ready to invoice" list, accepted quotes where work is marked complete but no invoice has been raised. Walk through it; raise invoices for any genuinely complete jobs.

For jobs that span quarters (deposit in Q1, balance pending in Q2), Karven recognises the deposit GST in Q1, you don't need to do anything special.

Step 2: Bank reconciliation

Reports → Bank reconciliation.

Upload your CSV bank export for the quarter. Karven matches each line against:

• Stripe payouts (matched on amount and date)
• Direct customer transfers (matched on reference + amount + customer name)
• Outflows (your supplier payments, payroll, etc., categorised but not deeply parsed)

What you're looking for is unmatched receipts. These are dollars in the bank that Karven didn't expect, typically a customer paid in cash, a customer paid an old invoice without a reference, or someone sent you money by mistake.

For each unmatched receipt: match it to the right quote/invoice manually, or record it as an external payment. Don't skip this, unmatched receipts are missed GST.

Step 3: Generate the BAS pre-fill

Reports → BAS → Generate for Q[n].

Karven produces the draft. Review each line:

• G1, Total sales. Should match your total invoices issued + manual receipts during the period.
• 1A, GST on sales. Should be ~9.09% of G1 (since G1 is inclusive). If it's wildly different, you've got GST-free supplies or a mistake.
• 1B, GST on purchases. From your supplier invoices and subbie RCTIs. Cross-check against your bank to make sure you haven't missed any.
• W1/W2, Wages and PAYG. From your payroll integration if connected.

For each line, Karven shows you the underlying records. Click any line to see the source documents.

Step 4: Manual adjustments

Common adjustments:

• Cash receipts you forgot to record. Add as external payments.
• Bad debts. If you wrote off an invoice this quarter, the GST you previously recognised gets reversed. Karven supports a "write off invoice" action that handles this automatically.
• Government grants / rebates received. Most are GST-free but some are taxable supplies. Add manually.
• Asset purchases over $1,000. Need to flag for the capital purchase line.

Karven prompts you about each common case. You confirm or skip.

Step 5: Bookkeeper review (optional)

If you use a bookkeeper, hit Share with bookkeeper and Karven generates a one-time read-only link. They review, leave notes against any line they want to question, and you respond.

You can also give your bookkeeper a permanent read-only seat on your Karven workspace, most prefer this. It costs you nothing.

Step 6: Lodge through the ATO

Karven doesn't lodge directly. Lodgement is via:

• The ATO Business Portal. Free, what most self-lodgers use. Log in with myGovID, navigate to BAS, paste the Karven numbers into the form, submit.
• A registered BAS or tax agent. They submit through their PLS (Practitioner Lodgement Service) connection.

The Karven BAS export is a structured CSV that follows the ATO's BAS field codes, so either you or your agent can paste it across line by line in a couple of minutes.

Step 7: Pay (or get paid)

If you owe GST net, pay by the 28th. The ATO portal shows your payment options (BPAY, credit card, EFT).

If the ATO owes you (your input credits exceeded your GST on sales), the refund lands in your nominated bank account within 14 days.

Special cases

Monthly BAS lodgers. Same flow but compressed. Karven supports monthly BAS, set it in Settings → Accounting → BAS frequency.

Annual GST return. If you're under the $75k threshold but voluntarily registered, you may be on annual lodgement. Karven supports this too.

Late lodgement. If you've missed a deadline, the ATO charges a penalty. Karven can still generate the BAS for any past period, there's no "expiry" on the data.

Records for the audit trail

Karven keeps everything for seven years, well past the ATO's standard five-year retention requirement. If you ever get audited:

• Every invoice (PDF + line-item data)
• Every payment (Stripe / bank / manual)
• Every subbie RCTI
• Every adjustment, with reason and timestamp
• The full BAS export for every period

One-click export of the full audit pack for any period.

A common gotcha

Don't lodge a BAS before you've reconciled the bank. The pre-fill is only as good as the data Karven has, and the bank is the source of truth for what actually moved.