Which Spouse Should Claim Medical Expenses? Pooling Family Costs and Choosing the Best 12-Month Window

Couples lose the medical expense tax credit by splitting the same receipts across two returns, or by leaving them on the return with the higher net income. Guide RC4065, Medical Expenses 2025, and Income Tax Folio S1-F1-C1 both start from one idea: one spouse claims the family's eligible total, then subtracts the lesser of 3 percent of that spouse's net income or a fixed dollar amount. For the 2025 amounts in the guide, that dollar amount is $2,834. A 2026 indexed ceiling was not printed on the guide or the folio chapter opened for this article, so it is not guessed. This page is education, not tax advice. The notice of assessment is the document that governs.

Why the lower-income spouse often claims: the 3%-of-net-income threshold

The credit is not a percentage of every receipt. Folio paragraph 1.3 says you claim the amount by which eligible expenses exceed the lesser of a fixed amount and 3 percent of your net income. The fixed amount is indexed. The folio tells you to read it on the CRA indexation chart. Guide RC4065, which is the 2025 guide, prints the figure used on the return: $2,834. Line 33099 is the eligible total minus the lesser of $2,834 and 3 percent of your line 23600.

A lower net income produces a lower 3 percent, until the cap binds. At $40,000, 3 percent is $1,200, and $1,200 is less than $2,834, so the hurdle is $1,200. At $94,500, 3 percent is $2,835, so the lesser amount is $2,834. That last step is arithmetic on the guide's $2,834, labelled as arithmetic. The guide's own couple, worked in full below, never hits the cap: both 3 percent figures are under $2,834. The medical expense tax credit guide is the list of what can enter the total. This page is who claims it, and over which months.

Folio paragraph 1.1 describes the credit as the lowest tax rate percentage multiplied by the two calculated amounts (your household pool, and other dependants). The folio chapter effective 15 August 2025 still says 15 percent for years after 2006. The CRA page "Last year tax rates and income brackets (2025)" prints 14.5 percent as the lowest federal rate for 2025, with a footnote that the rate decreased from 15 percent to 14 percent on 1 July 2025, making the full-year rate 14.5 percent. A Department of Finance note says the rate on most non-refundable credits tracks that lowest rate. Use the rate on the return for the year you file. This guide uses 14.5 percent only when it converts a 2025 claimable amount into a federal credit, and it says so. Provincial line 58689 is a separate form. It was not opened, so no provincial rate is printed.

Pooling both spouses' and minor children's expenses on one return

Line 33099 is the total eligible medical expenses you or your spouse or common-law partner paid for yourself, your spouse or common-law partner, and your or your spouse's children who were under 18 at the end of the tax year. Folio paragraph 1.2 is the same list. If you have, at the same time, both a spouse and a common-law partner, you claim expenses for one of them, not both. Paragraph 1.11 says a receipt in the name of either spouse is acceptable evidence of a medical expense of either, and the amount may be used by either, as they agree.

Pooling means one return holds the sum. It does not mean each spouse claims half. The same dollar cannot be used twice. Paragraph 1.9 says the expenses must not have been used in this credit, the disability supports deduction, or the refundable medical expense supplement for a previous year, and must not have been used by any other taxpayer. A plan reimbursement is generally out, unless it was included in income and not deducted elsewhere. How two workplace plans divide a bill before anything is left to claim is the coordination guide. What never went through a plan is the uninsured fees guide.

Travel kilometres, once they qualify, join this same pool. The distance rules are the medical travel guide. Do not create a second medical claim for the drive.

Choosing any 12-month period ending in the tax year

The guide says you can claim eligible expenses paid in any 12-month period ending in 2025 and not claimed by you or anyone else in 2024. Folio paragraph 1.9 says the same, and it adds a different window if the person died in the year: any 24-month period that includes the date of death. The guide repeats that 24-month rule for a person who died in 2025, if the expenses were not claimed for any other year. The period does not have to be 1 January to 31 December. A crown in August 2024 and a crown in May 2025 can sit in one window if that window ends in 2025 and the August bill was not already claimed.

The guide's worked couple chooses 1 July 2024 to 30 June 2025. That choice is the CRA's example, not a requirement to use July. Pick the 12 months, ending in the tax year, that put the most unreimbursed eligible costs above the hurdle. Then do not use those receipts again next year. The rest of the household's credits, employment amounts, and donations are the credits checklist. The 12-month medical window is not on that checklist in this detail.

Line 33199: other dependants and how the calculation differs

Line 33199 is not the family pool. It is each other dependant, calculated separately. The guide lists children 18 or older at the end of the year, or grandchildren, and parents, grandparents, brothers, sisters, uncles, aunts, nephews, or nieces who were residents of Canada at any time in the year and who depended on you for support. Folio paragraph 1.4 is the same family list. The residence requirement does not apply to a child or grandchild. Support, the folio says, is a question of fact: basic necessities such as food, shelter, and clothing, on a regular and consistent basis. If the person had income, you have to be able to show it was not enough for those needs.

The subtraction changes. On line 33199 you subtract the lesser of $2,834 and 3 percent of the dependant's net income, not yours. A dependant with a solid income can wipe out a modest bill. Children under 18 stay on line 33099, which is why their bills can be pooled with the parents even when a parent has the higher income.

When the lower-income spouse has too little tax to use the credit

The folio calls the credit non-refundable. It reduces Part I tax. If that tax is already zero, a larger claimable amount does not become a cheque. The lower-income spouse can still be the better claimer when they have some tax to reduce and a lower hurdle. They are the worse claimer when their tax is smaller than the credit the hurdle would produce, and the other spouse's tax can absorb a smaller claimable amount. Compare tax payable on both returns. Software that lets you toggle which spouse claims the line is an offer type. This page does not name a product.

There is a separate refundable medical expense supplement for working individuals with low incomes and high medical expenses. The guide says you may be able to claim it if you claimed medical expenses on line 33200 or the disability supports deduction on line 21500, you were resident in Canada throughout 2025, and you were 18 or older at the end of 2025. You must also meet income criteria. The paragraph opened here does not print those income dollars or a supplement maximum. Read line 45200. Do not treat the supplement as an automatic top-up because the non-refundable credit was wasted.

Worked comparison: same expenses, two different claimers

These figures are the guide's example, Richard and Pauline, not a household we observed. Their period is 1 July 2024 to 30 June 2025. Richard's expenses are $2,500. Pauline's are $2,000. Jen, their 16-year-old daughter, has $1,800. Rob, their 19-year-old son, has $1,300. The four amounts add to $7,600. Jen is under 18, so her $1,800 joins the parents. The line 33099 pool is $6,300. Rob is over 18, so his $1,300 is line 33199, and the guide says the parents must run the calculation using his net income. The guide does not print Rob's net income, so this page does not invent a claimable amount for him.

Pauline's net income is $55,000. Three percent is $1,650, which is under $2,834, so she subtracts $1,650 from $6,300 and could claim $4,650. Richard's net income is $42,000. Three percent is $1,260, so he subtracts $1,260 from $6,300 and could claim $5,040. The guide says it is better, in that case, for Richard to claim the expenses for himself, Pauline, and Jen. If you apply the 2025 lowest federal rate of 14.5 percent from the brackets page, 14.5 percent of $5,040 is $730.80 and 14.5 percent of $4,650 is $674.25. That is federal only, and only if the return has at least that much Part I tax to reduce. It is not a refund quote.