Each spring I hear from many retirees surprised to find they owe income tax, have been asked by the Canada Revenue Agency (CRA) to make quarterly instalments, or have had some or all of their Old Age Security (OAS) pension clawed back. You are not alone—this is a common situation for Canadian seniors. Here’s why it happens and what you can do to reduce the risk.
Income tax on retirement benefits
While you were working, your employer generally withheld payroll tax at source. If you had no other income, deductions or credits, that withholding often matched your tax obligation and many people received refunds each year due to deductions and credits reducing taxable income or tax payable.
Retirement changes that dynamic. Retirees typically have several income sources and many of those streams are not subject to regular withholding. For example, a defined benefit pension’s withholding assumes it is your only source of income for the year. If you add part-time employment, rental income or taxable withdrawals from non-registered investments, the withholding on that pension will usually be insufficient, and you may owe tax when you file.
Some common retirement income types either have no mandatory withholding or offer optional withholding only if you request it:
- Canada Pension Plan (CPP): CPP payments are not automatically taxed at source. You can request voluntary withholding when you apply for CPP or later, but it is not mandatory.
- Old Age Security (OAS): Like CPP, OAS is not automatically taxed at source. Service Canada can withhold tax on request. OAS is a means-tested benefit and may be reduced or recovered if your income is above the threshold (see section below).
- Registered Retirement Income Fund (RRIF): Minimum RRIF withdrawals do not require tax to be withheld. You may elect withholding, and any withdrawals above the minimum are subject to mandatory withholding by the financial institution at graduated rates depending on the amount.
Because of these rules, many retirees discover they owe tax at filing time unless they proactively arrange higher withholding or make instalment payments.
Why does the CRA ask for income tax instalments?
The CRA (and Revenu Québec for residents of Quebec) may require instalments if a taxpayer repeatedly owes tax. For most non-Quebec residents, owing more than $3,000 in tax in two consecutive years will prompt an instalment request. Quebec’s threshold for both federal and provincial requirements is $1,800.
Instalments are quarterly suggested payments intended to cover your current-year tax liability based on prior years’ tax. The CRA’s typical formula uses the tax owing from the second previous year for the March and June instalments and the previous year for the September and December instalments, with adjustments for amounts already paid.
Example: if you owed $10,000 for 2023 and $15,000 for 2024, the CRA might ask for $2,500 on March 15 and June 15, 2025, and $5,000 on Sept. 15 and Dec. 15, 2025. The March and June amounts equal one-quarter of the 2023 tax owing. The September and December amounts are based on the 2024 tax owing after subtracting the March and June payments, split in two.
These instalments are optional in the sense that you are not forced to pay them, but if you don’t and you still owe tax at year-end, you can face interest and penalties. To avoid instalments, many retirees increase withholding on income sources such as employer pensions or request withholding on CPP/OAS/RRIF distributions so annual withholding more closely matches expected tax.
Why is there a clawback on OAS and other means-tested benefits?
Several federal and provincial benefits are reduced or eliminated when a taxpayer’s income exceeds set thresholds. Common examples include:
- Old Age Security (OAS): OAS may be recovered if net income (line 23600) exceeds $93,454 in 2025. The recovery amount for the July-to-June OAS period is determined by your net income from the prior tax year.
- Guaranteed Income Supplement (GIS): GIS supports low-income OAS recipients and is reduced based on net income from the previous tax year. Eligibility and thresholds vary by marital status and whether a spouse or common-law partner receives OAS or the Allowance.
- Canadian Dental Care Plan (CDCP): The CDCP targets families without dental insurance and phases out for family net incomes above $70,000 and up to $90,000. Coverage and thresholds are income-based.
Other federal and provincial programs may also be income-tested and should be reviewed based on your specific circumstances.
Managing taxes in retirement
Key steps retirees can take to manage taxation include:
- Estimate your annual income and expected tax liability, accounting for CPP, OAS, RRIF minimums, investment income and any part-time work.
- Ask for voluntary tax withholding on CPP, OAS and RRIF payments if you prefer to have tax collected throughout the year and avoid a large balance owing at filing time.
- If you receive instalment notices, consider whether increasing withholding would be a simpler option to stay compliant and avoid instalments. If withholding is set too high, you will receive a refund when you file.
- Work with an accountant or financial planner to plan income timing and withdrawals to minimize clawbacks on benefits like OAS and GIS, and to smooth taxable income across years.
Many retirees are frustrated by taxes in retirement because income sources become more varied and because some benefits are income-tested. Understanding which payments are taxed at source, which are not, and how the CRA calculates instalments and clawbacks helps you make informed choices. If tax issues are a recurring problem, consult a tax professional or financial planner to create a strategy tailored to your income mix and benefit eligibility.