For educational purposes only. Not tax, legal, or financial advice. Tax laws change frequently. Consult a registered tax agent or CPA for your specific situation.
Australian self-employed people with chronic illness can vary their PAYG instalments each quarter to match actual income during health fluctuations, with no penalty for under-estimation if the estimate was reasonable at the time. The medical expenses tax offset was abolished from 1 July 2019 and is not available. DSP recipients can earn self-employment profit up to $218 per fortnight (singles) before the pension reduces at 50 cents in the dollar, with a complete cut-off around $2,575 per fortnight.
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Self-employment with chronic illness is a cash flow management problem layered on top of a health management problem. The tax rules are the same as every other sole trader, but the interaction between variable income, PAYG instalment variation, Disability Support Pension income tests, and superannuation catch-up rules decides whether you end up with a year-end tax bill you cannot pay during a flare.
The reality this serves
Self-employed Australians with chronic illness whose income fluctuates with health cycles. Conditions include autoimmune disorders, chronic fatigue, fibromyalgia, Crohn's disease, endometriosis, multiple sclerosis, and any condition that produces unpredictable flare-ups affecting work capacity. The cohort includes people who are self-employed because it is the only work pattern flexible enough to accommodate their health, not because they chose it over stable employment.
PAYG instalment variation for fluctuating income
If your prior return met the PAYG threshold, the ATO automatically enters you into quarterly instalments. You can vary the instalment rate or amount each quarter, which is critical when a health flare drops your income mid-year. The practical approach: base your variation on realistic income given expected downtime, not a best-case month. Re-estimate each quarter. If you have a bad health quarter, submit a new variation so instalments reduce. If you recover and pick up extra work, increase them again so you are not hit with a large year-end bill. There is no penalty for varying if your estimate was reasonable at the time, though the ATO can apply GIC on significant shortfalls.
PAYG instalment amounts or rates can be varied each quarter where the default amount will not reasonably reflect the expected tax for the year.(TAA 1953 Schedule 1, Division 45 (s 45-205))
Medical expenses tax offset: abolished
The medical expenses tax offset (including the later version for disability aids, attendant care, and aged care) only applied for 2015-16 to 2018-19 income years. It is not available from 1 July 2019. For 2025-26, medical and disability-related personal costs are not deductible unless they fall into a separate, specific deduction category. ADHD medication, specialist appointments, hospital stays, physiotherapy, and chronic illness management costs are personal expenses with no tax relief available.
The net medical expenses tax offset was phased out and is not available for income years from 2019-20 onwards.(ITAA 1997 s 61-370 (repealed); ATO medical expenses offset guidance)
DSP income test and self-employment profit
Services Australia assesses your business profit (not gross revenue) for the DSP income test. Single DSP recipients can earn up to approximately $218 per fortnight before DSP reduces, with a 50 cent taper above that threshold. The complete cut-off is around $2,575 per fortnight. Services Australia may average business income over periods and can look through to verify expenses are genuine. You must report changes in earnings promptly, including when illness forces you to reduce or stop work. Couples face a combined income free area of approximately $380 per fortnight with higher combined cut-off points.
DSP recipients have their pension reduced by 50 cents for each dollar of income above the income free area.(Social Security Act 1991 s 1064; Social Security Guide 3.6.1.32)
Super contributions and carry-forward for variable income years
The concessional contributions cap for 2025-26 is $30,000. If your total super balance is below the relevant threshold and you have unused concessional cap amounts from the previous five years, you can use catch-up (carry-forward) contributions. In good health years when you can work more, make larger deductible personal contributions using carry-forward room from past low-income years. This smooths tax and builds retirement savings against future earning capacity drops. In bad years, make little or no concessional contribution, preserving cap space for later. Concessional contributions are taxed at 15% in the fund (30% for high earners under Division 293).
Unused concessional contribution cap amounts from the previous five years can be carried forward if total super balance is below $500,000 at the prior 30 June.(ITAA 1997 s 291-20; SIS Act 1993)
Allowable expenses in context
Standard sole trader deduction rules apply (ITAA 1997 s 8-1). Chronic illness-specific judgement calls: Home-based business running costs (electricity, internet, phone, cleaning of workspace): deductible in proportion to business use. The revised fixed-rate method is 70 cents per hour. If your home is genuinely your place of business (dedicated area, primarily business use), you can also claim a portion of occupancy expenses (rent, mortgage interest, rates) based on floor area and usage. During flare-ups, your home may be the only place you can operate, which supports treating it as a genuine place of business. Income protection insurance premiums (held outside super, not bundled with life or TPD): deductible. Benefits received are taxable income. In good years, the deduction is at your higher marginal rate. In bad years, benefit payments are taxed at a lower effective rate because other income is down. Bookkeeping and tax agent fees: fully deductible. Cancellation insurance or business interruption cover that includes health-related triggers: deductible as a business expense. NOT deductible: personal medical expenses (medication, specialist appointments, hospital stays, physiotherapy). The medical expenses offset is abolished. Personal carer or support worker costs are not business deductions even if they enable you to work. NDIS-funded items cannot be double-claimed.
Support schemes
Disability Support Pension
Eligibility: Adults with a permanent physical, intellectual, or psychiatric condition that prevents work of 15 or more hours per week. Medical evidence and job capacity assessment required. You can work up to 29 hours per week and keep DSP provided you still meet medical and income tests.
NDIS participant funding
Eligibility: Permanent and significant disability that substantially reduces functional capacity for daily activities. Chronic illness may qualify where functional impact is severe and permanent.
ATO hardship and payment plans
Eligibility: Any individual or sole trader unable to pay tax debts on time. Serious hardship relief applies when payment would leave you unable to afford food, accommodation, clothing, or medical care. Hospital stays and documented illness strengthen GIC remission requests.
Frequently asked questions
Can I vary my PAYG instalments mid-year if a health flare drops my income?+
Yes. You can vary the instalment rate or amount each quarter by lodging a PAYG instalment variation through your activity statement. There is no penalty for varying if your estimate was reasonable at the time. The practical approach is to re-estimate each quarter based on actual income and realistic health outlook. If you under-estimate significantly and end up with a shortfall, the ATO can apply GIC on the difference, but this is distinct from a penalty for the act of varying. Varying promptly during a flare prevents over-payment that you would otherwise need to wait until assessment to recover.
Is there any tax offset for medical expenses in Australia?+
No. The medical expenses tax offset was fully phased out and is not available from 1 July 2019 onwards. There is no replacement offset for personal medical costs in the 2025-26 year. This means medication, specialist appointments, surgery, hospital stays, allied health, and chronic illness management costs have no direct tax benefit. The only indirect relief is through private health insurance (which avoids the Medicare Levy Surcharge if your income exceeds $93,000 single or $186,000 family) and NDIS funding for eligible participants (exempt income, ITAA 1997 s 52-180).
How does the DSP income test treat self-employment profit versus gross revenue?+
Services Australia assesses your business profit (income minus allowable business deductions), not gross turnover. They may average income over periods to smooth out lumpy self-employment earnings. The income free area for singles is approximately $218 per fortnight, above which DSP reduces by 50 cents in the dollar. You must report changes in earnings promptly, including when illness forces you to stop or reduce work. Super contributions claimed as a tax deduction are generally not deducted from income for Centrelink purposes, even though the ATO allows the deduction.
Should I use carry-forward super contributions in good health years?+
Yes, if your total super balance is below $500,000 at the prior 30 June. Unused concessional cap amounts from the previous five years can be carried forward. In good health years when income is higher, make larger personal deductible contributions (up to the accumulated cap) to reduce taxable income at your higher marginal rate and build retirement savings against future capacity loss. In bad years, contribute little or nothing, preserving cap space for recovery years. The concessional cap for 2025-26 is $30,000 (rising to $32,500 from 1 July 2026). Contributions are taxed at 15% in the fund.