ATO Payment Plan Calculator: Interest and Instalments
Also called: ATO payment plan interest calculator, GIC calculator.
Quick answer
This ATO payment plan calculator estimates the monthly instalment and general interest charge on a tax debt over the months you choose, at the ATO's rate for the quarter, and the loan rate that costs the same after tax. It is an estimate, not the ATO's calculation.
See what an ATO plan really costs you.
Set the debt, the months and any upfront payment. Each month shows the instalment and how much of it is general interest charge, which keeps accruing daily for as long as the plan runs.
Debts of $200,000 or less may be set up online; above that, you phone the ATO.
Longer than 2 years needs a call to the ATO.
Paid on day one, so GIC never accrues on it.
Not editable. The ATO resets GIC each quarter, so a real plan's interest will differ. Rates from the ATO's GIC rates page, read 27 September 2026.
25 per cent is the company rate for base rate entities and 30 per cent the full company rate. Sole traders use their own marginal rate in the formula on this page.
- Monthly instalment
- $4,432.24
- Total GIC
- $3,187
- Total paid
- $53,187
- Break-even, 25% tax
- 15.35%
$4,432.24 a month over 12 months on a $50,000 tax debt, no upfront payment, at the ATO's 11.51 per cent GIC rate for October to December 2026. Total GIC about $3,187.
Estimates only. This calculator is not a quote, an offer or an approval. The result is an estimate of interest on the figures you enter at the ATO rate shown, not the ATO's calculation. Nick Lim is an FBAA Accredited Finance Broker with Switchboard Finance.
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How does the ATO work out interest on a payment plan?
The ATO charges general interest charge (GIC) on the amount still owing, compounding daily, for as long as the plan runs; in this calculator each level instalment covers that month's GIC and the rest reduces the debt.
The GIC rate for a day is the base interest rate, which is the monthly average yield of 90-day Bank Accepted Bills, plus 7 percentage points, divided by the number of days in the year (Taxation Administration Act 1953, section 8AAD). The ATO publishes the result each quarter: 11.43 per cent a year, or 0.03131507 per cent a day, for July to September 2026, and 11.51 per cent a year, or 0.03153425 per cent a day, for October to December 2026. On its payment plans page the ATO says tax debts on a payment plan continue to accrue GIC, which compounds daily, and that paying in the shortest period will help reduce the GIC you pay (QC69390).
Monthly instalment = (tax debt − upfront payment) × r ÷ (1 − (1 + r)−n), where r = (1 + GIC rate ÷ 365)365 ÷ 12 − 1 is one month of daily compounding and n is the number of months.
This is the standard amortisation formula set out in the Reserve Bank of Australia's Research Discussion Paper 2021-10, Appendix A, with the monthly rate built from the ATO's daily rate. The calculator assumes:
- One GIC rate for the whole plan, from the quarter you pick. The ATO resets the rate every quarter, so a real plan's interest will differ.
- Equal monthly instalments paid in arrears, at the end of each month, with every month counted as 365 ÷ 12 days.
- GIC compounds daily on the balance still owing; an upfront payment is made on day one and comes off that balance.
- No new tax debts, penalties or missed instalments are added while the plan runs.
- Figures are rounded only for display.
The official tool is the ATO's own Payment plan estimator, which the ATO says "helps you work out how quickly you can pay off a tax debt and how much interest you'll be charged" (QC21930). The after-tax comparison with a loan is the part this page adds. If a plan has already defaulted, what the debt is costing you in interest is covered in our guide to a defaulted ATO payment plan.
What does a $20,000, $50,000 or $100,000 tax debt cost on a 12 month plan?
About $3,187 in GIC on a $50,000 debt over 12 months at the October to December 2026 rate of 11.51 per cent, with instalments of about $4,432 a month; $20,000 costs about $1,275 and $100,000 about $6,374. The table shows both quarters' rates, because the rate steps up on 1 October 2026.
| Tax debt | Monthly instalment, 11.43% (Jul to Sep 2026) | Total GIC, 11.43% | Monthly instalment, 11.51% (Oct to Dec 2026) | Total GIC, 11.51% | Total paid, 11.51% |
|---|---|---|---|---|---|
| $20,000 | $1,772.14 | $1,266 | $1,772.89 | $1,275 | $21,275 |
| $50,000 | $4,430.35 | $3,164 | $4,432.24 | $3,187 | $53,187 |
| $100,000 | $8,860.70 | $6,328 | $8,864.47 | $6,374 | $106,374 |
Sources: GIC annual rates of 11.43 per cent (July to September 2026) and 11.51 per cent (October to December 2026) from the ATO's General interest charge rates page (ato.gov.au, QC16145, last updated 4 September 2026, read 27 September 2026); amortisation formula from RBA Research Discussion Paper 2021-10, Appendix A (rba.gov.au, November 2021, read 27 September 2026). Estimates, not the ATO's calculation: one rate held for the whole plan, equal monthly instalments in arrears, months of 365 ÷ 12 days, no upfront payment; instalments to the cent, totals rounded to the dollar.
Time costs more than the quarterly rate change. Stretching the $50,000 debt to 24 months lowers the instalment to about $2,344 but lifts the GIC to about $6,244, and 36 months takes it to about $9,411. To set a plan instalment beside a loan repayment on the same amount, run the figures through the business loan repayment calculator.
Is an ATO payment plan cheaper than a business loan?
It depends on the loan's rate after tax: GIC incurred on or after 1 July 2025 is not tax deductible, while interest on a business loan may be, so a loan only costs less after tax when its rate is below the GIC rate divided by one minus your tax rate.
The ATO's reminder on the change says any GIC incurred on and after 1 July 2025, regardless of whether the debt relates to an earlier income year, is no longer tax deductible, under the Treasury Laws Amendment (Tax Incentives and Integrity) Act 2025 (ATO media release, 10 June 2025). On the other side, the ATO's list of common business operating expenses includes interest on money borrowed for producing assessable income and for income tax obligations (QC33867), and where an expense is part business and part private, only the business share can be claimed (QC33725).
Break-even loan rate = GIC rate ÷ (1 − tax rate)
| Tax rate | GIC 11.43% (Jul to Sep 2026) | GIC 11.51% (Oct to Dec 2026) |
|---|---|---|
| Company, 25% (base rate entity) | 15.24% | 15.35% |
| Company, 30% (full rate) | 16.33% | 16.44% |
Sources: GIC rates from the ATO's General interest charge rates page (ato.gov.au, QC16145, last updated 4 September 2026, read 27 September 2026); company tax rates of 25 per cent for base rate entities and 30 per cent for other companies from the ATO's Changes to company tax rates page (ato.gov.au, QC54063, last updated 4 September 2026, read 27 September 2026); GIC not deductible from 1 July 2025 per ATO QC33415 (last updated 10 June 2026, read 27 September 2026). Qualifier: compares nominal annual rates only; loan fees, compounding, term and security are not included, and whether loan interest is deductible depends on what the money is used for.
Read the break-even as a threshold for comparison, not a recommendation. Below it, a loan's after-tax rate is lower than GIC, but fees, a longer term, security over property and the loss of the ATO plan's flexibility can outweigh the difference. Sole traders pay tax at individual marginal rates, so the same formula applies with their own rate in place of the company rate.
Worked figures at the 30 per cent rate sit in our comparison of a working capital loan against ATO debt at the GIC rate, and the business debt consolidation guide covers when finance is and is not the right lever for tax debt. How those facilities are structured is on the working capital loans page. Your accountant can confirm whether the interest would be deductible for you.
Who can set up a payment plan, and how long can it run?
If you owe $200,000 or less you may be able to set up a payment plan yourself through ATO online services or the self-help phone line, and a debt above that, or a plan longer than 2 years, needs a call to the ATO.
Sole traders set a plan up through ATO online services linked to myGov; companies and other businesses use Online services for business. When you set up online, the ATO gives an upfront amount you need to pay alongside suggested instalments, and says it will help you save on interest by guiding you to pay what you owe in the shortest time (Setting up a payment plan, QC106182, last updated 24 February 2026). There is no fixed maximum length on those pages; the ATO describes a plan as spread over the shortest possible fixed period of time.
Small businesses with annual turnover under $2 million and recent activity statement amounts of $50,000 or less, overdue for up to 12 months, may be eligible for an interest-free plan paid by direct debit within 12 months. The other conditions include a good payment and lodgment history, being unable to obtain finance through normal business channels and showing ongoing viability; the ATO says GIC is still incurred but is remitted automatically while that plan is maintained (Alternative payment plans, QC106184, last updated 3 September 2026). This calculator does not model that plan.
If you are looking at a loan instead, lenders read the evidence around a tax debt before the balance, which our note on borrowing to pay an ATO debt sets out.
What else do people ask about ATO payment plans?
How much interest does the ATO charge on a payment plan?
The ATO charges general interest charge on the balance still owing, compounding daily, at 11.43 per cent a year for July to September 2026 and 11.51 per cent for October to December 2026. At 11.51 per cent, a $50,000 debt paid over 12 months carries about $3,187 in GIC on this calculator's estimate.
How long can you have a payment plan with the ATO?
The ATO's payment plan pages set no fixed maximum; they describe a plan as spread over the shortest possible fixed period of time. Debts of $200,000 or less may be set up online, and you need to phone the ATO if you owe more or need longer than 2 years.
Is GIC tax deductible in 2026?
No. GIC incurred on or after 1 July 2025 can't be claimed as a deduction, even where the debt relates to an earlier income year, while GIC incurred before 1 July 2025 can still be claimed.
Does an upfront payment reduce the interest?
Yes. GIC accrues daily on the balance still owing, so an upfront payment stops that amount attracting GIC; on a $50,000 debt over 12 months at 11.51 per cent, $10,000 upfront cuts the estimated GIC from about $3,187 to about $2,549.
Can the ATO refuse a payment plan?
Yes, the ATO says that depending on the circumstances you may not be eligible for a payment plan on the terms you suggest or at all, and our defaulted ATO payment plan guide covers the next steps.