A totalization agreement is a bilateral social security treaty that does two things: it assigns a cross-border worker to one country’s contribution system at a time, so the same earnings never fund two payroll systems, and it lets credits earned in each country combine so a split career still qualifies for a benefit. The United States has 30 of these agreements in force, including one with Canada that has run since August 1, 1984.[Social Security Administration, U.S. International Social Security Agreements, 2026-07] Canada operates its own, larger network of more than 50 agreements, and the two lists do not match.[Canada Revenue Agency, International social security agreements and the Canada Pension Plan, 2026-07]
The call for this library’s readers: if your working years split between the US and Canada, the 1984 agreement makes the pension math whole, and since the Windfall Elimination Provision was repealed in January 2025 a CPP cheque no longer shrinks your US Social Security. The exposure sits further south. Costa Rica, Panama, Belize, and the Dominican Republic have no agreement with either Washington or Ottawa, so a remote worker who becomes locally covered in one of those markets contributes twice and combines nothing. If you are already retired and drawing benefits, most of this page is not your problem; totalization governs contributions and eligibility, not a benefit you have already qualified for.
The two problems a totalization agreement solves
Social security systems are territorial, and the default rules of two countries routinely capture the same worker. The US taxes its citizens’ self-employment income at 15.3% for Social Security and Medicare no matter where they live and work.[IRS, Self-Employment Tax (Social Security and Medicare Taxes), 2026-07] Canada requires CPP contributions on self-employed earnings of Canadian residents at a base rate of 11.9%.[Canada Revenue Agency, CPP contribution rates, maximums and exemptions, 2026-07] A US-citizen consultant living in Toronto answers to both rules at once, paying into two systems on one income, and neither foreign tax credits nor the income tax treaty helps, because social security contributions are not income tax.
The second problem bites decades later. Each system has a minimum service requirement: US Social Security retirement needs 40 credits, roughly ten working years. A career split 8 years in the US and 25 in Canada fails the US minimum outright: eight years of contributions, nothing back.
Coverage rules: one system at a time
The default is territoriality: you contribute where you physically work. The exception is the detached-worker rule: an employee sent to the other country on a temporary assignment, five years or less under the US-Canada agreement, stays in the home system and is exempt from the host system.[Social Security Administration, Totalization Agreement with Canada, 2026-07] Hire locally and the host system takes over.
Self-employed workers get a cleaner rule under the US-Canada agreement: Article V assigns them to the country where they reside. The Toronto consultant contributes to CPP only and files proof with the IRS to escape the 15.3% self-employment tax.
Credit combining: a split career still qualifies
When benefit time comes, each country counts the other’s credits toward its own minimum. The 8-year US worker needs at least 6 US quarters of coverage; past that floor, SSA counts the Canadian years toward the 40-credit test.[Social Security Administration, Totalization Agreement with Canada, 2026-07] The benefit is then prorated: the US pays only for the US years, at a rate derived from the US earnings record. Canadian credits fill the eligibility gap. They never inflate the US cheque.
The traffic runs both ways, but Canada needs the help less often. A CPP retirement pension requires only one valid contribution, so combining matters on the Canadian side mainly for CPP disability and survivor benefits, and for Old Age Security. OAS is residence-based: 10 years of Canadian residence to collect in Canada, 20 to collect abroad. The agreement lets US coverage periods count toward those thresholds, the difference between an OAS cheque in Arizona and no OAS at all.[Social Security Administration, Totalization Agreement with Canada, 2026-07]
How the US-Canada agreement pays a split career
No money moves between the systems and no credits transfer; each country pays its own prorated benefit, and the retiree collects two deposits. A worker with 12 years of US coverage and 25 years of CPP contributions retires with a US Social Security benefit sized to the 12 US years, a CPP pension sized to the 25 Canadian years, and, with enough combined residence, OAS on top. Quebec runs a parallel arrangement covering QPP, so a Montreal career lands in the same place as a Toronto one.
The agreement decides who you contribute to; the income tax treaty decides who taxes the benefits once they flow. The treaty side, including the pension articles, is covered in the Canada-US tax treaty guide and the double taxation explainer.
The WEP is repealed, and dual retirees are the winners
For four decades the Windfall Elimination Provision was the asterisk on every US-Canada retirement plan. WEP cut the US Social Security benefit of anyone who also drew a pension from work not covered by US Social Security, and CPP counted. Advisors built whole strategies around reaching 30 years of substantial US earnings to escape it.
That planning problem no longer exists. The Social Security Fairness Act, signed January 5, 2025, repealed both WEP and the Government Pension Offset for benefits payable after December 2023. SSA paid retroactive amounts back to January 2024 to roughly 3.2 million beneficiaries, most deposited by the end of March 2025, with adjusted monthly benefits flowing from April 2025.[Social Security Administration, Social Security Fairness Act: WEP and GPO update, 2026-07]
For a dual CPP-and-Social-Security retiree, both benefits now pay at full calculated value. Anyone who deferred a CPP application, or shaped their filing sequence, to soften a WEP haircut should re-run the numbers. The constraint that drove those choices is gone.
Which of this library’s countries have an agreement
The eight property markets this site covers split into a European tier with full coverage and an American tier with almost none.
| Country | Agreement with the US | Agreement with Canada |
|---|---|---|
| Mexico | No. Signed in 2004, never entered into force | Yes, in force since May 1, 1996 |
| Spain | Yes, in force since April 1, 1988 | Yes |
| Portugal | Yes, in force since 1989 | Yes, in force since 1981 |
| Italy | Yes, in force since 1978 | Yes; revised agreement in force since October 2017 |
| Costa Rica | No | No |
| Panama | No | No |
| Belize | No | No |
| Dominican Republic | No | No |
Mexico is the strange case. The US signed a totalization agreement with Mexico in June 2004 and never transmitted it to Congress, the statutory step that would bring it into force; after more than two decades, the working assumption is that it never will. Canada closed the same gap in 1996: the Canada-Mexico agreement has been in force since May 1, 1996, complete with credit combining and certificates of coverage.[Proclamation Declaring the Agreement on Social Security Between Canada and the United Mexican States in Force May 1, 1996, 2026-07] A Canadian who spends working years in Mexico can combine credits; an American doing the same thing cannot.
The four southern markets have no agreement with anyone relevant here, the same gap they show on the income tax side in countries with no tax treaty, and the absence has two practical meanings readers tend to conflate. For a retiree, it means little: US Social Security pays US citizens in most foreign countries, Costa Rica and Panama included, and CPP pays abroad without conditions. OAS is the one to watch, since paying it outside Canada takes 20 years of Canadian residence, and with no agreement there are no foreign periods to backfill a shortfall. For a worker, the missing agreement is the whole story: no coverage assignment, no exemption certificate, no credit combining. Years paid into a local system there stand alone.
Certificates of coverage for remote workers
The certificate of coverage makes the coverage rules real. Issued by the home-country authority, it names the worker and the assignment and certifies that home-system contributions continue, exempting the worker and employer from host-country social security for its term.
On the Canadian side, the CRA issues certificates under each agreement; for US assignments the request is Form CPT56, which covers employees and the self-employed under Article V, and a certificate can run up to 60 months.[Canada Revenue Agency, Form CPT56, Certificate of Coverage under the CPP pursuant to Article V of the Agreement on Social Security between Canada and the United States, 2026-07] On the US side, employers and self-employed workers request them through the Social Security Administration’s international-programs office. The employer keeps the certificate, the worker keeps a copy, and it is the answer when the host country’s payroll authority asks why no local contributions are arriving.
Three scenarios cover most of this site’s readers. A Canadian employee working remotely from Spain, Portugal, or Italy for a Canadian employer sits under Canada’s agreement with each of those countries; a CRA certificate keeps them in CPP and out of the local system for a temporary stay. An American in the same three countries gets the same result through the US agreements. In Costa Rica, Panama, Belize, or the Dominican Republic there is no certificate to request; whether the local system captures a foreign remote worker turns on local employment law and enforcement practice. Employer-of-record arrangements, common for remote hires there, create local employment, which means local social charges by design.
One boundary: a certificate of coverage settles social security contributions only. It does not decide tax residency, which follows day counts and ties under the rules in the tax residency guide, and it does not touch income tax withholding.
Frequently asked questions
Does a totalization agreement reduce my income taxes?
No. It governs social security contributions and benefit eligibility. Income tax relief comes from the tax treaty and foreign tax credits, on separate paperwork.
Can I transfer CPP credits into US Social Security, or the reverse?
No. Each country counts the other’s periods only to test whether you qualify, then pays from your own record there. A split career produces two cheques, not one merged pension.
Do I lose Social Security or CPP by retiring in a country with no agreement?
Generally no. US Social Security is payable to US citizens in most countries, and CPP pays abroad without a residence condition. The exception is OAS, which requires 20 years of Canadian residence to be paid outside Canada; with no agreement, no foreign periods can help meet that test.
Is the US-Mexico agreement ever going to take effect?
No sign of it. It has never been transmitted to Congress, which the law requires before it can enter into force. After 20-plus years, prudent planning treats it as nonexistent.
How long can a certificate of coverage keep me in my home system?
Up to 60 months under the US-Canada agreement, with extensions when both authorities agree. Assignments intended to be permanent shift you to the host system from the start.
Where this fits in the library
Totalization is one layer of a cross-border move; the taxes hub holds the rest, including how double taxation gets relieved and where the residency lines sit. Canadians planning a permanent exit should read the departure tax guide before triggering non-residency, and anyone holding property in two countries at death has the cross-border estate planning problem regardless of pensions. For the country-level tax stack on a purchase, start with your market’s buyer page: Mexico for Canadian buyers or Costa Rica for American buyers.