Is Claiming Medical Expenses Worth It in Canada? The 3% Threshold Math

You paid for an ADHD assessment out of pocket, you have been seeing a therapist, and the pharmacy keeps printing receipts you shove in a drawer. Tax season arrives and the question is blunt: is it worth claiming medical expenses on taxes in Canada, or is the credit so small that the receipt hunt costs more than it returns?

The answer is a formula, not a feeling. Once you know the threshold and roughly what you spent, you can decide in two minutes. This post gives you the formula, a worked example built around ADHD care, and the two choices (which 12 months, whose return) that change the result more than people expect.

The threshold: 3% of net income or the annual cap, whichever is lower

The medical expense tax credit does not pay you back for the first chunk of what you spend. You can only claim eligible expenses above a threshold, and the threshold is the lower of two numbers: 3 per cent of your net income (line 23600 of your return) or a fixed dollar cap that is indexed each year. The cap was $2,759 for the 2024 tax year and is $2,834 for 2025. So if your net income is $60,000, your threshold is $1,800 (3 per cent). If your net income is $120,000, 3 per cent would be $3,600, but the cap applies instead, so your threshold is $2,834.

Everything above the threshold earns a non-refundable federal credit of 15 per cent, plus a provincial credit at your province's lowest tax rate (5.05 per cent in Ontario, for example; Quebec runs its own version). Non-refundable means it reduces tax you owe; it will not generate a refund by itself if you owe nothing. There is also a separate refundable medical expense supplement for people with modest working income, worth up to $1,464 for 2024, which tax software calculates automatically if you qualify.

Which ADHD costs count? The assessment, if it was done by a practitioner CRA recognises in your province (a physician, nurse practitioner or psychologist, for most provinces); the assessment fee answer has the detail. Therapy fees, if the therapist's profession is on CRA's authorised list for your province; here is the province-by-province picture for therapy. Prescription medication, for the portion your plan did not reimburse. Premiums you paid for a private health plan, including the amount deducted from your pay. The fee a clinician charged to fill out a form such as the T2201. Travel, if you had to go more than 40 km one way for care that was not available closer.

Worked example: an assessment, therapy and prescriptions

Take an Ontario adult with net income of $58,000. Threshold: 3 per cent is $1,740, which is below the cap, so $1,740 it is. Over a 12-month window they paid:

• Online ADHD assessment: $500 (our current fees are on the pricing page; use whatever you actually paid)
• Twelve sessions of CBT with a registered social worker at $160: $1,920
• Prescriptions after the benefits plan paid its share: $480
• Health plan premiums deducted from pay, shown on the T4: $720

Total eligible expenses: $3,620. Subtract the threshold: $1,880 is claimable. Federal credit at 15 per cent: $282. Ontario credit at 5.05 per cent: $95. Combined, about $377 off their tax bill, for perhaps 20 minutes of receipt gathering. That is worth it by most people's hourly rate.

Now the other case. Someone with the same income who only paid $900 in prescriptions and premiums is below the $1,740 threshold. Their credit is zero, and the honest advice is to not bother this year. The rule of thumb: if your household's out-of-pocket health spending in a year is clearly more than 3 per cent of the lower earner's net income, claim. If it is clearly less, skip it. If it is close, add it up; the year with the assessment in it usually tips over.

Choosing any 12-month period ending in the tax year

This is the part most people miss. You do not have to claim January to December. You can claim any 12-month period that ends in the tax year, as long as none of those expenses were claimed on an earlier return. Everyone on the same return must use the same period.

Why it matters for ADHD care: assessments and therapy rarely line up with the calendar. Suppose your assessment was in November 2025 and therapy ran from December 2025 to April 2026, with medication starting in January. On your 2026 return you could choose the window of 1 November 2025 to 31 October 2026, capturing the assessment, every therapy session and ten months of prescriptions in one claim. Split across two calendar years, each half might fall under the threshold; together, they clear it comfortably. If you already filed 2025 without claiming anything, those November and December receipts are still available for the 2026 window.

Claiming on the lower-income spouse's return

Either spouse or common-law partner can claim the whole family's medical expenses, including the other partner's and any children under 18. Because the threshold is 3 per cent of net income, the lower earner's threshold is lower, so more of the same spending becomes claimable.

Rerun the example with the $3,620 claimed by a partner whose net income is $34,000. Threshold: $1,020. Claimable: $2,600. Federal: $390. Ontario: $131. Total about $521, which is $144 more than the same receipts on the higher earner's return. The one condition: the lower earner needs enough tax payable to use a non-refundable credit. If their income is low enough that they owe no tax after basic credits, the credit evaporates, and it is better claimed by the other partner. Most tax software will try both and show you the difference; if it does not, run the return twice.

Receipts, prescriptions and what CRA may ask for later

You do not send receipts with an electronic return, but CRA reviews medical expense claims often, and the request for documents tends to arrive months later. Keep everything for six years. What a good file looks like:

• An official receipt for each assessment or therapy session showing the practitioner's name, profession or registration number, the date and the amount. A credit card statement alone is not enough.
• A year-end prescription printout from your pharmacy, which lists every fill with its prescription number. Ask at the counter in January; most pharmacies produce it on the spot.
• Your benefits plan's claim history, showing what was reimbursed, so you can prove you only claimed the unreimbursed portion. Checking your benefits plan explains where to find this.
• Your T4 or a pay stub showing health plan premiums, and any invoice for premiums you paid directly.
• For travel claims, the appointment confirmation and distance.
• A note of which 12-month window you used, so next year's claim starts the day after it ended.

One ADHD-specific habit that makes this painless: a single folder, physical or in your email, named for the tax year, and a rule that every medical receipt goes in there the day it arrives. The claim then takes ten minutes rather than an evening.

What to do this week

1. Find your net income on last year's notice of assessment and multiply by 0.03. That is your threshold unless it exceeds the cap.
2. Add up what you spent on the assessment, therapy, unreimbursed prescriptions and premiums over the best 12-month window you can find.
3. If the total beats the threshold, email every clinic you paid and ask for an annual receipt, and ask your pharmacy for the year's printout.
4. If you have a partner, work out whose threshold is lower and whether they owe enough tax to use the credit.
5. Open a folder for next year now. Future receipts go in it unread.

For the broader list of what ADHD-related costs are claimable, including which professions count in each province, see claiming ADHD care as a medical expense on Canadian taxes.