Every spring, I review prior-year returns for new clients and find the same thing: money left on the table. Not from aggressive planning — from perfectly ordinary claims that people simply didn't know existed.
Here are ten of the most commonly missed expenses and claims on Canadian personal tax returns.
1. Medical Expenses Beyond the Obvious
Most people remember the dentist bill. They forget:
- Premiums for private health and dental plans — including the employee-paid portion deducted off your paycheque (check your pay stub or T4 details)
- Travel medical insurance purchased for trips
- Travel for medical care — if you had to travel at least 40 km one way for treatment not available locally, you may claim transportation; at 80 km or more, meals and accommodation can come into play too. This one matters in communities where specialists mean a drive into the city.
Bonus tip: medical expenses can be claimed for any 12-month period ending in the tax year, and it's usually better claimed by the lower-income spouse. Two levers most software users never pull.
2. Carrying Charges and Investment Fees
Fees paid to manage your non-registered investments, and interest on money borrowed to earn investment income, are deductible. Fees inside your RRSP or TFSA are not — but the non-registered ones add up fast and routinely go unclaimed.
3. Union and Professional Dues
Dues to a union or a professional body required to maintain your professional status are deductible. If your employer reports them on your T4, software usually catches it — but dues you paid personally often slip through.
4. Child Care You Didn't Think Counted
Daycare, yes — but also day camps, summer camps, before-and-after school programs, and payments to caregivers. Child care expenses generally must be claimed by the lower-income spouse, and receipts matter.
5. Moving Expenses
If you moved at least 40 km closer to a new work location or to attend full-time post-secondary studies, eligible moving costs — movers, travel, real estate commissions on selling your old home, legal fees, even some temporary living costs — can be deductible against income at the new location. This claim is big, legitimate, and chronically overlooked.
6. Home Office for Employees
The COVID-era flat rate is gone, but the detailed method is alive and well. If your employer requires you to work from home and signs a T2200, you can claim a reasonable portion of utilities, rent, internet, and more. If you work from home regularly and have never asked your employer about a T2200, ask.
7. Student Loan Interest
Interest on government student loans (Canada Student Loans and provincial equivalents) generates a credit — and unused amounts can be carried forward up to five years. Interest on a bank line of credit used for school does not qualify, which is exactly why people assume none of it does.
8. Tuition Carryforwards and Transfers
Unused tuition credits carry forward indefinitely, and students can transfer up to $5,000 of current-year federal tuition to a parent, grandparent, or spouse. I regularly meet graduates sitting on years of unclaimed carryforwards because they "didn't owe tax back then." That's the point — they're waiting for you now.
9. The FHSA Deduction
Contributions to a First Home Savings Account are deductible like an RRSP — up to $8,000 per year ($40,000 lifetime) — and withdrawals for a qualifying first home are tax-free. If you opened one and forgot to claim the deduction, or you're a renter who hasn't opened one, this is worth a conversation.
10. Donations and the Disability Tax Credit
Two catch-alls that reward looking backward:
- Charitable donations can be carried forward up to five years and pooled on one spouse's return — often producing a better result than claiming small amounts annually.
- The Disability Tax Credit is missed constantly, and once approved, CRA can reassess up to ten prior years. For qualifying individuals and their supporting family members, this can mean thousands in retroactive refunds.
The Real Lesson
Tax software is good at math and bad at asking questions. It calculates what you enter — it doesn't know about the 45-km drives to the specialist, the T2200 you never requested, or the tuition credits gathering dust from 2019.
If any of these sound like you, prior-year returns can generally be adjusted going back ten years. At CMP Accounting, a T1 review is part of how we onboard every new personal tax client — get in touch and let's make sure nothing's been left behind.