Quarterly PAYG instalments have been the default for small and medium business since 2000. Budget 2026-27 announced an opt-in monthly cycle starting 1 July 2027 — ATO-formula automated, penalty-protected for honest mistakes, optional for most. This post walks who should switch, who should stay quarterly, and how the mechanics differ from the existing PAYG withholding (which is a separate scheme).
What changes
Under the current rules, eligible small and medium businesses pay quarterly PAYG income tax instalments. The ATO calculates the instalment from the prior year's tax position, varied for inflation. The business pays the same amount four times a year regardless of how the current year is actually trending.
From 1 July 2027, the ATO will offer an opt-in monthly cycle:
- Instalment frequency: monthly instead of quarterly (12 payments / year instead of 4)
- Calculation: ATO-approved formulas embedded in accounting software, auto-adjusting to current business position
- Penalty protection: where variations are unintentional and the approved formula was used, the ATO will not impose penalty interest
- Eligibility: opt-in for most small and medium businesses; mandatory for taxpayers with a history of non-compliance
Note: PAYG instalments vs PAYG withholding
Two different PAYG mechanisms, often confused. PAYG withholding is what you withhold from employee wages, super, or contractor payments — that's unchanged by this measure. PAYG instalments are pre-payments of your own income tax (for the company / sole trader / trust) made through the year — that's what the Budget changed. We have a fuller explainer at /learn/payg-withholding.
When monthly wins
Seasonal businesses
Hospitality, retail, tourism, agriculture — revenue is concentrated in specific quarters. Under quarterly, the off-season instalment is the same as the peak quarter, draining cash when the business is least liquid. Monthly tracks the actual revenue curve.
High-growth businesses
A company doubling revenue year-on-year. Quarterly instalments based on prior-year position massively under-collect, leaving a large balancing payment at year end. Monthly auto-adjusts upward as revenue grows — cash flow stays predictable.
Lumpy revenue businesses
Project-based consultants, construction with milestone billings, agency businesses landing big clients irregularly. Quarterly smooths over the lumps too aggressively, monthly is closer to reality.
When quarterly stays better
Stable, predictable revenue
SaaS with subscription revenue, professional services on retainer, established trade businesses with steady jobs. Monthly adds 8 extra payment events per year for marginal benefit. Quarterly keeps the cadence simple.
Small operations without integrated software
The penalty-protection safe harbour requires using the ATO-approved formula via supported software. Businesses still on paper books or spreadsheets won't get the safe harbour and won't get the auto-adjustment. Monthly adds friction without the benefit.
Businesses already comfortable with quarterly
If your cash flow handles quarterly instalments fine and there's no end-of-year squeeze on balancing payments, the switch costs admin without buying you anything.
Mandatory monthly — the exception
Taxpayers with a history of non-compliance (late lodgement, late payment, prior PAYG defaults) will be moved to monthly mandatorily. This isn't a penalty, it's a structural tightening — smaller, more frequent collections reduce the dollar amount the ATO has to chase if a taxpayer falls behind. If you receive an ATO letter compelling monthly, talk to us about getting compliant before the switch becomes permanent.
How to decide
Before the 1 July 2027 commencement, model your last two years' revenue against both quarterly and monthly instalment scenarios:
- Coefficient of variation in monthly revenue (high CV = monthly helps)
- Year-end balancing payment size under quarterly (large balancing = monthly would've smoothed)
- Current accounting software (must be ATO-compatible for the safe harbour)
- Admin capacity for 8 extra payment events per year
We'll run this analysis for clients at no extra cost as part of their FY26 or FY27 year-end review. Bring the conversation if your business sits in any of the "monthly wins" categories above.
Related small-business measures from the same Budget
- $20,000 IAWO permanent — capital purchases continue to qualify for immediate expensing.
- Loss carry-back revived — companies in loss can refund prior-year tax against the current loss.
- $1,000 instant work-related deduction — sole-trader employees benefit from the personal-tax side.
Sources
- Budget 2026-27 tax reform page (budget.gov.au/content/04-tax-reform.htm)
- Treasurer's 2026-27 Budget speech (ministers.treasury.gov.au)
- Pitcher Partners — Budget 2026-27 business measures
- NSW Small Business Commissioner — Federal Budget 2026-27 SME update