US Social Security in Canada: 85% taxable, 50% if received before 1996

How much of a US Social Security benefit does Canada tax?

Article XVIII(5)(a) of the Canada US treaty makes a US social security benefit paid to a Canadian resident taxable only in Canada, taxed as though it were a CPP benefit, except that 15% of the benefit is exempt from Canadian tax canada.ca. Canada then adds its own relief for older recipients: paragraph 110(1)(h) of the Income Tax Act deducts a further 35% when the client has been resident in Canada and receiving the benefits continuously since before 1996 laws-lois.justice.gc.ca. Together that's the 50% the CRA describes canada.ca.

The 15% runs through paragraph 110(1)(f)(i), which deducts any amount exempt from Canadian tax because of a tax treaty laws-lois.justice.gc.ca. Benefits paid for your client's children are the children's income, even when your client receives the payments canada.ca.

Where does each amount go on the T1?

Report the full Canadian dollar amount of the US Social Security benefits on line 11500, including any US Medicare premiums paid on your client's behalf canada.ca. On the SSA statement that means starting from the net benefits in box 5, which the SSA doesn't reduce for Medicare premiums deducted from the payments irs.gov.

Convert at the Bank of Canada rate for the day each payment was received, or use the average annual rate when the payments came at different times during the year canada.ca. For monthly benefits, the annual average is the usual choice; see foreign income exchange rates.

Claim the 15% or 50% on line 25600 and name the deduction in the space provided. On a paper return, attach a note if your client claims more than one type of line 25600 deduction canada.ca.

The part your client doesn't deduct on line 25600 counts as foreign pension income for the $2,000 pension income amount on line 31400; the deducted part doesn't canada.ca.

The 50% deduction saves $1,470 of federal tax on C$30,000 in 2026

Two Ontario clients, both 72, each receive US Social Security worth C$30,000 in 2026 after conversion, plus $20,000 of other taxable income. Ana moved to Canada in 2012. Ben has lived in Canada and drawn US benefits every year since 1994.

Both stay inside the first 2026 federal bracket, 14% on taxable income up to $58,523 canada.ca, so Ben's extra $10,500 deduction saves $1,470 of federal tax ($10,500 × 14%), plus Ontario tax on the same $10,500. Net income is identical, which matters for the next section.

The 50% chain is fragile. Paragraph 110(1)(h) needs a single unbroken period that starts before 1996 and ends in the current year, with Canadian residence throughout and US benefits received in every taxation year of it laws-lois.justice.gc.ca. A year living outside Canada or a year with no US benefits ends that period, and a new one can't start before 1996, so the client drops to 15% for good. A surviving spouse keeps 50% only if the deceased qualified in the year of death and the survivor has stayed resident in Canada since canada.ca.

Why the line 25600 deduction doesn't shield OAS or the age amount

Paragraphs 110(1)(f) and (h) are deductions in computing taxable income laws-lois.justice.gc.ca, so they sit below net income on the return. The OAS recovery tax works from line 23400 canada.ca, and the age amount works from line 23600 canada.ca. Both see 100% of the US benefit.

The OAS recovery tax is 15% of net income above $95,323 for the 2026 income year, and $93,454 for 2025 canada.ca. Take a client with $80,000 of other net income and C$30,000 of US Social Security in 2026.

The $675 gap is the cost of the deduction landing after net income. Projections that net the 15% off the benefit before computing the clawback understate it. Strategies to bring net income down are on the OAS clawback page.

Does the US tax the benefit or withhold anything?

No, for a Canadian resident. IRS Publication 915 lists Canada among the treaty countries whose residents are exempt from US tax on their benefits, and separately lists Canada among the countries where US citizens living there are exempt too irs.gov. The citizen exemption holds because Article XXIX(3)(a) carves paragraph 5 of Article XVIII out of the treaty's saving clause canada.ca. The US filing obligations of a citizen client are on US citizens living in Canada.

Without the treaty, a nonresident alien has 85% of the benefits taxed at 30%, which is 25.5% of the gross, shown on Form SSA-1042S irs.gov. If that withholding appears for a Canadian resident, usually because the SSA has an old address or residence on file, the fix is a refund from the SSA or the IRS. It isn't a foreign tax credit on the T1, and the CRA can't refund tax paid to another country canada.ca. See the foreign tax credit page for what does qualify.

Railroad retirement is the exception in practice. Tier 1 benefits fall under the same treaty paragraph canada.ca, but the RRB withholds US tax unless your client files Form RRB-1001 with citizenship and residence details irs.gov.