Social Security Administration

Totalization Agreements

The other treaty network — the one that decides whether you pay social security twice, and it does not cover the same countries.

Every rate on this page is cited to the treaty article that authorises it. Treaty texts last read September 21, 2026.

Quick answer
A totalization agreement stops you paying social security contributions to two countries on the same earnings, and lets you combine credits from both to qualify for a pension. 31 are in force. It is not your income tax treaty — different agency, different paperwork, and a different list of countries. Brazil has a totalization agreement and no tax treaty; China has a tax treaty and no totalization agreement.
Key takeaways
  • Two networks, not one. Income tax treaties come from Treasury; totalization agreements come from the Social Security Administration. Having one tells you nothing about the other.
  • Without an agreement you can owe social security to both countries on the same earnings — around 15% of pay, and no income tax treaty touches it.
  • The claim is made with a certificate of coverage, given to your employer. Nothing goes to the IRS.
  • A detached workersent abroad temporarily — usually five years or less — normally stays in their home country’s system.
  • Foreign social security contributions are generally not creditable against US income tax, because they are not income tax.

What a totalization agreement does

Two things: it assigns you to one country’s social security system, and it lets you add up credits from both.

1. They stop you paying into two systems at once
Without an agreement, someone sent from one country to work in the other can owe social security contributions to both on the same earnings — a straight double charge of roughly 15% that no income tax treaty touches. The agreement assigns you to one system and excuses you from the other.
2. They let you add up credits from both countries
A career split between two countries can leave you short of the minimum in each and entitled to a pension from neither. Totalization combines the periods so you qualify, though each country still pays only for the part of your career spent in it.

The first purpose is the one most people meet. A German engineer posted to Texas for three years can, without an agreement, owe German contributions because she is employed by a German company and US social security and Medicare because she is working in the United States — roughly 15% of pay, twice, on the same salary. The agreement picks one.

Source: SSA POMS GN 01701.005 — International Social Security (Totalization) Agreements. Read 2026-09-21.

It is not your tax treaty

Different agency, different tax, different paperwork, different countries. Having one tells you nothing about the other.

This is the single most useful thing on this page, and almost nobody sets it out. People say “we have a treaty with the US” and mean one of two entirely separate instruments.

The two networks compared
Income tax treatyTotalization agreement
What it coversFederal income tax — withholding rates, residency, which country taxes whatSocial security and Medicare contributions, and pension credits
Who negotiates itTreasury, with the IRS administering itThe Social Security Administration
How you claim itForm W-8BEN before payment, or Form 8833 with your returnA certificate of coverage, given to your employer
Which countriesAbout 60 countries31 countries, and not the same 31
Does it help with the other?No. An income tax treaty does not reduce social security tax.No. A totalization agreement does not reduce income tax.

The four cases that prove it

Countries where the two networks disagree
CountryIncome tax treatyTotalizationWhat that means
BrazilNoYesA totalization agreement in force since 1 October 2018, and no income tax treaty at all. Brazilians are told constantly that there is 'a treaty' — there is, and it does nothing for their income tax.
ChinaYesNoAn income tax treaty with an unusually generous students article, and no totalization agreement. A Chinese national working in the US can owe social security contributions to both systems with no relief.
MexicoYesNoAn income tax treaty in force, and a totalization agreement that was signed but has never entered into force. Signed is not in force, and only in force counts.
IndiaYesNoAn income tax treaty and no totalization agreement, which is why Indian nationals on temporary US assignments pay into US social security without being able to use it unless they reach forty quarters.
Signed is not in force
Mexico’s totalization agreement has been signed for years and has never entered into force. Only entry into force counts, and a signed-but-dormant agreement gives you nothing to show an employer.

Indian nationals are the largest group affected by this gap. nritousa.com covers the forty-quarters problem for Indian workers in more depth than we do here.

The countries, and when each came into force

31 agreements, ordered by date — because the shape of the network is part of the answer.

It starts in Western Europe in the late 1970s and stays there for a generation. Asia arrives in 2001, Latin America not until 2018. If your country is not on this list, the reason is usually that no agreement has ever been concluded rather than that one lapsed.

Totalization agreements in force, as recorded in SSA POMS GN 01701.005 on September 21, 2026
CountryIn force sinceNote
ItalyNovember 1, 1978—
GermanyDecember 1, 1979—
SwitzerlandNovember 1, 1980—
BelgiumJuly 1, 1984—
NorwayJuly 1, 1984—
CanadaAugust 1, 1984—
United KingdomJanuary 1, 1985Implemented in two phases: coverage provisions from 1 January 1985, benefit provisions from 1 January 1988.
SwedenJanuary 1, 1987—
SpainApril 1, 1988—
FranceJuly 1, 1988—
PortugalAugust 1, 1989—
NetherlandsNovember 1, 1990—
AustriaNovember 1, 1991—
FinlandNovember 1, 1992—
IrelandSeptember 1, 1993—
LuxembourgNovember 1, 1993—
GreeceSeptember 1, 1994—
Korea, SouthApril 1, 2001—
ChileDecember 1, 2001—
AustraliaOctober 1, 2002—
JapanOctober 1, 2005—
DenmarkOctober 1, 2008—
Czech RepublicJanuary 1, 2009—
PolandMarch 1, 2009—
Slovak RepublicMay 1, 2014—
HungarySeptember 1, 2016—
BrazilOctober 1, 2018—
UruguayNovember 1, 2018—
IcelandMarch 1, 2019—
SloveniaFebruary 1, 2019—
RomaniaSeptember 1, 2026—

Agreements are added from time to time — Romania’s is the most recent, effective 1 September 2026 — and others have been signed without entering force. Check the SSA source below before relying on the absence of a country.

Source: SSA POMS GN 01701.005 — International Social Security (Totalization) Agreements. Read 2026-09-21.

Which country's system do you pay into?

Normally the country where you are working — unless you were sent there temporarily, in which case you usually stay at home.

Territoriality is the default
You generally pay into the system of the country where you are actually working.
A detached worker stays home
Someone sent by an employer to work temporarily in the other country — typically for five years or less — usually stays in their home country's system and is exempt from the host country's.
Self-employment is assigned by residence
Most agreements assign a self-employed person to the country where they reside, which avoids two sets of self-employment tax on the same profit.
A five-year posting, and what happens in year six
A British employee sent to New York by a UK employer stays in the UK system under the detached-worker rule and pays no US social security or Medicare, on a certificate of coverage from HMRC. If the posting is extended past the agreement’s limit, coverage generally shifts to the US system — and the certificate stops being the answer. That transition is the point at which people are most often assessed for contributions they thought they were exempt from.

The certificate of coverage

It is the whole claim. No certificate, no exemption — regardless of what the agreement says.

What is it?
A document proving you are covered by one country's social security system, so the other country's contributions do not apply to you.
Who issues it?
The social security agency of the country whose system you remain in — not the IRS, and not your employer.
What do you do with it?
Give it to your employer, who stops withholding the other country's contributions. Keep a copy: it is the evidence that the exemption was correct.
What if you cannot get one?
Revenue Ruling 92-9 provides an alternative procedure for someone who cannot secure a certificate from their home country.
Nothing here goes to the IRS
This is the structural difference from the rest of this cluster. There is no Form 8833 equivalent and no line on your return. The certificate goes to your employer, and the exemption happens in payroll.
Source: SSA POMS GN 01701.005 — International Social Security (Totalization) Agreements. Read 2026-09-21.

Adding up credits from both countries

Totalization lets you qualify using combined periods — but each country still pays only for its own share of your career.

The second purpose is quieter than the first and matters later in life. US Social Security generally requires forty quarters of coverage — ten years — before it pays anything at all. Someone who worked eight years in the United States and twenty-five in Germany can fall short of both countries’ minimums and receive nothing from either.

Under an agreement, the periods are combined to test whether you qualify. What you are then paid is proportional: the United States pays a benefit based on your US earnings only, and the other country does the same for its own. Totalization buys you eligibility, not a second full pension.

For what the US side then pays and when, see the Social Security payment schedule.

Frequently asked questions

What is a totalization agreement?

A bilateral agreement between the United States and another country that does two things: it stops you paying social security contributions to both countries on the same earnings, and it lets you combine credits earned in both to qualify for a pension. It is negotiated by the Social Security Administration, is entirely separate from any income tax treaty, and covers a different list of countries.

Which countries have a totalization agreement with the US?

31 countries have one in force, from Italy in 1978 to Romania in 2026. The network is heavily European in origin and reached Latin America only recently — Brazil in 2018, Uruguay a month later. Large economies notably absent include China, India and Mexico, whose agreement was signed and never entered force.

Is a totalization agreement the same as a tax treaty?

No, and this is the most common misunderstanding on the subject. An income tax treaty covers income tax; a totalization agreement covers social security contributions. They are negotiated by different agencies, claimed with different paperwork, and cover different countries. Brazil has a totalization agreement and no income tax treaty; China has an income tax treaty and no totalization agreement.

What is a certificate of coverage?

The document that proves you are covered by one country’s social security system, so the other country’s contributions do not apply to you. It is issued by the social security agency of the country you are staying in — not by the IRS — and you give it to your employer, who then stops withholding. Keep a copy: it is your evidence the exemption was correct.

Do I pay social security in both countries if there is no agreement?

Often, yes — and nothing relieves it. That is the situation for nationals of China, India and Mexico working in the United States: an income tax treaty may reduce their income tax and does nothing at all about the roughly 15% of earnings that social security and Medicare take between employer and employee. No foreign tax credit is available for it either, because it is not an income tax.

Does Mexico have a totalization agreement with the US?

No — not one in force. An agreement was signed but has never entered into force, and only entry into force counts. Mexican nationals working in the United States therefore pay US social security and Medicare in full, even though the US–Mexico income tax treaty is in force and does reduce withholding on some income.

How long can I stay on my home country's system?

Typically five years, under the detached-worker rule most agreements share. Someone sent by their employer to work temporarily in the other country stays in their home system and is exempt from the host one for that period. Beyond it, you generally move to the host country’s system. The exact limit is set by each agreement, so check the one that applies to you.

Can I claim a foreign tax credit for foreign social security contributions?

Generally not. The foreign tax credit reaches income taxes, and a social security contribution is not an income tax. Where a totalization agreement applies, the answer is to not pay the second contribution at all rather than to credit it — which is precisely what the certificate of coverage achieves. See the foreign tax credit page for what is and is not creditable.

Sources

Agreements change. Before relying on the presence or absence of a country, check the SSA source directly — this page records what it said on September 21, 2026.

Related

Tax Treaty Benefits & Country Lookup
Free tool: is there a treaty with your country, what rate, and which form claims it
Foreign Tax Credit
The relief that works when no treaty does — credit against deduction
Form W-8BEN
The form your broker or payer asks for, and what it actually does
Form 8833
When you must disclose a treaty position, and what to write on each line
Educational information, not tax advice

Every rate and article on this page is cited to the treaty text it comes from, so you or your accountant can check it. Treaty provisions turn on facts we do not know about you — residency, beneficial ownership, limitation-on-benefits conditions and the savings clause can all change the answer. Read the article before you rely on the number, and take advice on anything material.