Medical expenses can add up quickly — and the medical expense tax credit can significantly reduce your tax bill. If you forgot to claim them on a prior year’s return, you can go back and recover that credit. There’s no time pressure; you have up to 10 years.
How the Medical Expense Tax Credit Works
The Medical Expense Tax Credit (METC) is a non-refundable federal tax credit of 15% on eligible medical expenses above the threshold. Each province also offers a provincial credit at the relevant provincial rate.
The threshold: You can only claim expenses exceeding the lesser of:
- 3% of your net income (line 23600), or
- $2,759 (for the 2025 tax year; adjusted annually for inflation)
Example: If your net income is $65,000, your threshold is $1,950 (3% of $65,000). If you paid $5,000 in eligible expenses, your claimable amount is $3,050. The federal credit would be $3,050 × 15% = $457.50.
The 12-Month Period Trick
Medical expenses don’t have to be claimed January to December. You can claim any consecutive 12-month period ending in the tax year. This means if you had a large expense in November 2024, you could claim from December 2023 to November 2024 — potentially sweeping in more expenses from the prior year.
This strategy can significantly increase your claim. You may want to run the numbers for multiple 12-month windows to find the period that produces the largest credit.
What Expenses Are Eligible?
CRA maintains a detailed list at canada.ca. Common eligible expenses include:
| Expense | Eligible? |
|---|---|
| Prescription medications | Yes |
| Dental treatment (fillings, crowns, dentures, implants) | Yes |
| Eyeglasses, contact lenses, laser eye surgery | Yes |
| Orthodontics | Yes |
| Hearing aids and batteries | Yes |
| Crutches, wheelchairs, walkers | Yes |
| Travel to medical care (>40km, via cheapest route) | Yes |
| Accommodation for medical travel (>80km from home) | Yes |
| Fertility treatments, IVF | Yes |
| Attendant care / nursing home | Yes (with conditions) |
| Gluten-free food (celiac disease, with certification) | Yes (incremental cost) |
| Over-the-counter medications | No |
| Gym memberships | No |
| Cosmetic surgery (elective) | No |
| Vitamins and supplements | No |
Claiming for Multiple Family Members
You can claim eligible expenses for your entire household on one person’s return. Always run the calculation both ways:
- Lower-income spouse: Their 3% threshold is smaller, so a greater portion of expenses exceeds it. This usually produces the larger credit.
- Higher-income spouse: If the lower-income spouse has no tax payable, the credit is wasted (it’s non-refundable). In that case, the higher-income spouse may generate more actual tax savings.
How to Fix a Prior Year’s Return
Step 1: Gather receipts
Collect all eligible medical receipts for the year(s) in question. You don’t need to submit them with your adjustment, but CRA may request them in a review. Keep them for at least six years.
Step 2: Identify the optimal 12-month period
Add up expenses by different 12-month windows to find the period where your total expenses most exceed the threshold.
Step 3: File a T1 Adjustment
Online (fastest): CRA My Account → “Change my return” → select the tax year → update line 33099 (you and your spouse’s medical expenses) with the corrected amount.
By mail: Complete Form T1-ADJ and mail with a brief explanation of what changed. You don’t need to attach receipts unless requested.
CRA can adjust returns up to 10 years back.
Medical Expenses for Other Dependants
For expenses paid for a parent, grandparent, older child, sibling, or other dependant who relies on you for support, claim on line 33199. The calculation is different — you subtract the dependant’s own net income from the eligible expenses, then apply the $2,759 or 3% threshold.