BAS pre-fill walkthrough

The Business Activity Statement is the quarterly (or monthly) reckoning with the ATO. For most tradies it eats half a day to a full day of pulling numbers together, and that's if your bookkeeping is tidy. Karven shortens that to ten minutes by pre-filling the BAS from the data you've already generated through normal use of the app.

What Karven can pre-fill

The big ones:

• G1, Total sales. Sum of all sent and accepted invoices in the period, GST-inclusive.
• 1A, GST on sales. GST component of G1.
• 1B, GST on purchases. GST claimed on subbie RCTIs and supplier invoices recorded in Karven.
• W1, Total salary, wages, and other payments. From your payroll integration if you've connected one.
• W2, PAYG withheld. Likewise from payroll.

What Karven can't pre-fill:

• T1-T9, PAYG instalments. These come from the ATO's pre-fill data, not from your business activity.
• 5A, Wine, fuel, or other excise. Not relevant for trades.

The pre-fill flow

1. Reports → BAS → Generate for Q[n].
2. Karven shows you the candidate numbers with a one-line "here's where this came from" link next to each.
3. You click through any line you want to verify. Karven shows the underlying invoice list, with totals.
4. You can add manual adjustments (e.g. a cash receipt that didn't go through Karven, or a supplier invoice you recorded outside the app).
5. Approve and export.

The export is a PDF summary and a CSV that maps line-by-line to the ATO BAS form. You can copy the numbers into the ATO portal manually, or use Karven's Xero/MYOB sync to push them through your accounting software.

Cash vs accruals

The BAS report defaults to cash basis, sales count when the customer pays, not when you invoice. This is what most small tradies use (and the ATO's default for businesses under $10m).

To switch to accruals: Settings → Accounting → BAS basis → Accruals. Karven recalculates immediately. Pick one and stick to it; switching mid-year creates reconciliation headaches.

What about deposits?

Deposits are a normal taxable supply at the time you receive them. Karven recognises the GST on the deposit at receipt and the GST on the balance at final invoice. Both end up in G1 / 1A across the correct periods.

If a job spans two BAS periods, deposit in Q1, balance in Q2, Karven splits the GST recognition correctly. You don't have to think about it.

What about variations?

Variations are treated as separate supplies at the time they're approved by the customer. They appear on the BAS in the period they were approved. If you've raised a variation in Q1 but it's not paid until Q2 and you're on accruals, the GST is in Q1's BAS. On cash, it's in Q2's.

Cross-checking against bank

Karven offers a Bank reconciliation mode where you upload a CSV from your business account and Karven matches receipts against accepted quotes. Any mismatches surface as warnings on the BAS pre-fill page. This catches:

• Customer payments that bypassed Karven (they paid you in cash, or transferred outside the portal).
• Stripe payouts that haven't landed yet (shown as "in transit" rather than received).
• Refunds or chargebacks.

If you're disciplined about using Karven for every transaction, the reconciliation pass usually finds nothing. If you're not, it's where you'll catch the gaps.

Lodging through the portal

Karven doesn't lodge the BAS for you. The ATO's BAS portal is where lodgement happens, you log in with your myGovID, paste in the pre-filled numbers (or upload via the integration if you're using a registered tax agent), and submit.

We've deliberately not built ATO lodgement into Karven. The ATO's process changes regularly, and getting it wrong has real consequences. Karven gets the numbers right; you (or your bookkeeper) do the final submit.

Working with a bookkeeper

If you've got a bookkeeper, you can invite them to Karven with a read-only role: Settings → Team → Invite bookkeeper. They see your BAS, your invoices, your subbie payments, but they can't change customer-facing data, raise quotes, or hit "send" on anything.

Most bookkeepers prefer this to working from a Xero export, because Karven shows the source documents (the actual quote, the actual invoice) and not just the accounting summary.

Records you need to keep

The ATO requires you to keep records that support every BAS for five years. Karven keeps everything, invoices, RCTI, customer signatures, payment records, for the life of your account plus a seven-year retention after closure. If the ATO ever audits, you've got the receipts.

A common gotcha

Don't forget your January quarter is October-December. The financial-year quarters and the calendar quarters don't line up. Karven labels them by date range, not by Q-number, to avoid that confusion.