Many Canadians do not realize they have become common-law for tax purposes until a benefit changes or the CRA asks questions. For example, the GST/HST credit is recalculated using combined family income once you qualify. The tax definition of common-law is not based on whether you call each other spouses. It depends on the CRA’s tests, which this page sets out along with how to report a change in status. For filing in general, see the Canadian tax filing guide.
The basic CRA test
You are usually common-law for tax purposes if either of these is true:
| Test | Rule |
|---|---|
| 12-month rule | You have lived together in a conjugal relationship for 12 continuous months |
| Child rule | You share a child by birth or adoption, or one partner has custody and the other supports the child |
If you meet either test, CRA expects you to report common-law status.
What counts as living together?
Living together does not mean you are physically under the same roof every night without exception. Temporary absences usually do not break the count.
Examples that often do not reset the 12-month period:
- work travel
- short-term schooling elsewhere
- visiting family
- temporary medical or family-related absences
What is a conjugal relationship?
CRA looks at the relationship as a whole.
Common indicators include:
- shared home or routine living arrangement
- shared finances or household responsibilities
- presenting yourselves socially as a couple
- emotional and economic interdependence
Common situations people ask about
| Situation | Likely Tax Answer |
|---|---|
| Living together 8 months, no child | Usually not common-law yet |
| Living together 12+ months | Usually yes |
| Have a child together after 4 months | Often yes sooner |
| Keep separate bank accounts | Can still be common-law |
| One partner travels often for work | Still may be common-law |
Benefits and credits affected by common-law status
Once CRA recognizes you as common-law, income-tested benefits are recalculated using combined family net income instead of your individual income, and some credits become available to share between partners. That is why some people see benefits drop after becoming common-law.
| Program | What changes |
|---|---|
| GST/HST credit | One payment per couple (not two), based on combined income |
| Canada Child Benefit | Calculated on combined family net income |
| Canada Workers Benefit | Switches to the family calculation |
| Child care expense deduction | Depends on which partner has the lower income |
| Spousal amount | May become claimable; see the tax benefits of getting married |
| Medical and donation claims | Can be pooled on one partner’s return; see the medical expense tax credit |
| Spousal RRSP | You can contribute to one using your own contribution room |
| Ontario Trillium Benefit / provincial credits | Most provincial income-tested credits also use combined income |
How each partner’s return then handles these credits is covered in should I file taxes as a couple or separately?
How to update your marital status with CRA
You are legally required to notify CRA when your marital status changes. Use one of these methods:
- Online: Log into CRA My Account → Profile → Update marital status
- Form RC65: Download and mail CRA Form RC65 (Marital Status Change)
- Tax return: Update the marital status field on your T1 return when you file
- My Account app: Status changes can be made through the CRA My Account mobile app
CRA asks to be told by the end of the month following the month the change occurred. For example, if you moved in together in June and completed 12 months the following June, the deadline to notify CRA is the end of July that year.
If you were already receiving benefits as a single person, CRA will recalculate from the date of the status change. In some cases, you may have received more benefit than you were entitled to, and CRA will recover this through future benefit reductions or by requesting repayment.
What if you do not update CRA?
That can cause problems.
You may face:
- benefit overpayments
- reassessments
- repayment demands
- possible interest charges
The issue is usually not that CRA is looking for a label. It is that the wrong marital status changes benefit calculations. A marital status left out of date is one of the common tax mistakes in Canada.
Separating after common-law: tax implications
If you separate after being recognized as common-law, you revert to single status for tax purposes once you have been separated for at least 90 days. During those 90 days, you are still considered common-law.
After separation:
- Your marital status with CRA needs updating again
- Benefits recalculate on individual income
- Spousal RRSP contributions stop (no new contributions, but the account remains)
- If you have children, which parent claims the CCB has to be settled (usually the primary caregiver)
- Dividing significant property or registered accounts can have tax consequences; RRSPs on separation or divorce covers the registered-plan side, and a tax professional can review larger estates
Common-law for tax vs provincial family law
Tax treatment and family-law rights are not always the same.
| Topic | Tax Rules | Family Property Rules |
|---|---|---|
| Common-law definition | Federal CRA rules | Provincial law varies |
| Property division on breakup | Not a CRA issue | Depends on province |
If you want the broader legal and financial picture, see common-law relationships in Canada.
Bottom line
You are likely common-law for tax purposes if you have lived together in a conjugal relationship for 12 continuous months or you meet the child-related rule sooner. Once that happens, CRA expects your marital status to be updated, and your benefits and tax calculations may change.