How are US Social Security benefits taxed for Canadian residents?

Why Canada, not the US, gets to tax the benefit

Article XVIII(5) of the Canada-US tax treaty assigns the exclusive right to tax US Social Security benefits paid to a resident of Canada to Canada alone. This is a deliberate reallocation: without the treaty, US Social Security paid to a nonresident alien would normally face US withholding under the same rules that apply to other US-source income. The treaty overrides that outcome specifically for Social Security, so a Canadian resident collecting a US benefit reports and pays tax on it in Canada, not the United States.

The same reallocation runs in the other direction. Canadian CPP and OAS paid to a US resident are taxable only in the US under the mirror provision, with the same 85%-inclusion mechanics applied on the US side. Our answer on how CPP and OAS are taxed for a US resident covers that side of the same rule.

Only 85% of the benefit is actually taxed

On a Canadian T1, you report the gross US Social Security benefit received for the year, converted to Canadian dollars, and then claim a deduction equal to 15% of that amount on line 25600. The net effect is that 85% of the benefit is included in income and taxed at your regular marginal rate, the same percentage the US applies when it taxes Social Security paid to its own residents at the higher end of the income scale. There is no special lower rate or separate schedule; the taxable 85% simply adds to your other income for the year.

Stopping US withholding before it starts

Nonresident aliens generally face US withholding on Social Security, but the treaty is meant to eliminate that for Canadian residents entirely. The Social Security Administration applies withholding based on the country of residence it has on file for you, and the published rate for Canada under the treaty is nil, so a Canadian resident's benefit is typically paid without any US tax withheld once the SSA has a current Canadian mailing address on record. If withholding has been happening anyway, confirm your address and country of residence are correctly recorded with the SSA rather than assuming a form needs to be filed with the IRS.

Being a US citizen does not change the outcome

A US citizen living in Canada might expect the treaty's usual saving clause to pull Social Security back into US taxation, since that clause generally lets the US tax its citizens on worldwide income as if the treaty were not there. Social Security is one of the specific exceptions the treaty carves out of the saving clause, so a US citizen resident in Canada gets the same result as a Canadian citizen: the benefit is taxed only in Canada, at the 85%-inclusion rate, with no US tax on it. Our dual citizen tax guide covers the saving clause and where it does and does not reach.

The Windfall Elimination Provision no longer reduces the US benefit

For years, a separate US rule called the Windfall Elimination Provision reduced the US Social Security benefit of someone who also received a pension from work not covered by US Social Security, which caught many Canadians who also collect CPP. The Social Security Fairness Act, signed into law in January 2025, repealed the Windfall Elimination Provision along with the related Government Pension Offset, retroactive to benefits payable after December 2023. A Canadian who saw an earlier US Social Security benefit calculation reduced because of CPP should have had that corrected, and anyone still seeing an old reduced amount should follow up with the Social Security Administration directly.

Where this fits with your other retirement income

US Social Security is reported alongside CPP, OAS, RRIF withdrawals and any other pension income on the same Canadian return, and it factors into calculations that look at total income, such as OAS clawback thresholds and provincial benefit eligibility, the same as any other income source. Because only 85% counts, a household relying heavily on US Social Security often has a somewhat lower effective tax rate on that portion of retirement income than on fully taxable pension income of the same size.

What to do when you first start receiving the benefit

The year benefits begin is when most reporting mistakes happen. New recipients sometimes assume the entire deposit is tax-free because no US tax was withheld, or they misreport the full amount without applying the 15% deduction, either of which produces the wrong Canadian tax bill. The Social Security Administration issues an annual benefit statement, form SSA-1099 or its foreign equivalent for a nonresident, and that statement is the source document to use for the T1 rather than adding up bank deposits, since deposit timing and exchange rates can make the two figures diverge. Keep the annual statement with your tax records the same way you would a T4 or T5.

How we handle US Social Security on Canadian returns

We confirm the treaty position applies to a client's specific facts, make sure the SSA has the correct country of residence on file so no US withholding is taken in the first place, and apply the 85% inclusion correctly on the T1 alongside other retirement income. For clients weighing where to retire, we look at CPP, OAS and Social Security together rather than one benefit at a time, which often comes up as part of a broader US tax preparation engagement for a retiree with income on both sides of the border.

Source: Social Security Administration — Totalization Agreements.