Swiss social-security number (AVS/AHV) and student payslips

Last checked: 5 Oct 2026. Unofficial student guide, not EPFL or government advice: confirm on the linked official pages before you act. Unfamiliar abbreviation? See the Glossary.

Companion to AVS for students, Student tax, Working while studying and Residence tax vs income tax. This is orientation, not tax or payroll advice. No withholding rates are quoted here; use Vaud’s official calculators or ask ACI / your employer.

What this page is for

How newcomers usually get and read their Swiss social-security number (AVS / AHV / OASI number), how that relates to tax paperwork, and what a Swiss salary certificate (and a typical monthly payslip) shows when you take a student job. Official ESTV, AVS and Canton Vaud sources only.

The number: AVS / AHV / OASI (not a separate “US-style” tax ID)

Switzerland’s personal social-security identifier is the 13-digit AVS number (French AVS, German AHV, English OASI). It starts with 756 and is anonymous and lifelong. Federal pages describe it as the social-security number used across first-pillar schemes and, increasingly, as a personal identifier in other public administration.

There is no separate everyday “Swiss tax ID” for individuals on the pages we checked that replaces this number. When employers fill the federal salary certificate (Form 11), ESTV’s guide requires the 13-digit AVS number (and date of birth) on the form. Tax letters from Vaud use a taxpayer number (numéro de contribuable) once ACI knows you; that is an ACI file number, not the AVS number.

Sources:

BSV, Die AHV-Nummer
ZAS, FAQ OASI number for individuals
ESTV / CSI, Guide to the salary certificate (Form 11), from tax year 2026 (field “Numéro AVS”)

How you usually receive the number

BSV states that people who live or work in Switzerland receive an AHV/AVS number. Allocation is often automatic (birth in Switzerland, settling in Switzerland). When it is not automatic, certain bodies can request one:

Employers register workers who have no number with a compensation office.
Educational institutions (for example universities) request a number for foreign students in Switzerland.
Health insurers can request one in some special cases.

Where to find it once allocated

On the Swiss health-insurance card (printed since 2010; starts with 756).
From your employer if you work.
From your educational institution if you study.
From your commune of residence if you live in Switzerland and do not work.
From the competent AVS compensation office if you are self-employed.

An OASI insurance certificate (card) is no longer compulsory and is not issued automatically; knowing the number is enough for most authorities. You can still request a certificate via the OASI/DI channels described on ch.ch, Requesting an OASI card.

Sources: BSV page above · ZAS FAQ · ch.ch OASI card

Students (timing)

BSV states that educational institutions (for example universities) request an AHV number for foreign students in Switzerland. BSV’s student FAQ (German hub) adds that, as a rule, the school applies no later than six months after admission; contact your school first. ZAS notes that establishments that use the number can look it up or request allocation; not knowing the number should not block most procedures. One exception ZAS names is creating an electronic patient record, where you must provide the number yourself.

Practical EPFL-area tip: if your LAMal card already shows a 756… number, you already have it. If a first employer asks for it before the card arrives, ask Student Services (student.services@epfl.ch) or the HR desk of that employer which channel they use.

EPFL public pages: EPFL’s AVS insurance page covers minimum student contributions, not number allocation. No EPFL-branded public how-to names the internal unit or form used to request AVS numbers for Bachelor/Master students (unlike ETH’s published myStudies flow). Federal rule still stands: educational institutions may request the number for foreign students (BSV). Practical channels: LAMal card (756…), employer HR if you work, or Student Services (student.services@epfl.ch) to ask which EPFL channel applies to you.

Sources:

Monthly payslip vs annual salary certificate

Document	Who issues it	What it is for
Monthly payslip (bulletin de salaire)	Your employer’s payroll	Shows that month’s gross pay, social-insurance deductions, net pay, and often withholding tax
Salary certificate (Form 11, certificat de salaire / Lohnausweis)	Employer, usually once per calendar year (or when you leave)	Official annual attestation for tax; ESTV publishes the form and guide

ESTV: employers certify benefits paid to employees on the official salary certificate / pension statement form. Guides and Form 11 PDFs: ESTV, Salary certificate / Pension statement · FR hub.

Keep both. ACI and VaudTax workflows expect the annual certificate; monthly slips help you spot errors early (wrong permit category, missing AVS number, odd deductions).

What Form 11 (and a typical payslip) usually show

From the ESTV / CSI Guide valid for salary certificates from tax year 2026. Field names below are the official French labels; German/English appear on the trilingual form.

Identity / period

Numéro AVS (13 digits) and date of birth
Calendar year covered; salary period if not the full year
Employer and employee addresses

Pay and deductions (selected official figures)

Gross salary components leading to salaire brut total (ch. 8)
Ch. 9 - Cotisations AVS/AI/APG/AC/AANP: employee share only of old-age/survivors, disability, loss-of-earnings, unemployment and non-occupational accident insurance contributions withheld from salary. Employer shares are not listed here. An AANP deduction means you have non-occupational accident cover through that employer; see Accident insurance for students.
Ch. 10 - Prévoyance professionnelle (2e pilier): employee occupational-pension contributions when applicable (see next section)
Ch. 11 - Salaire net: gross (ch. 8) minus ch. 9 and 10
Ch. 12 - Retenue de l’impôt à la source: total withholding tax deducted during the year for foreign employees without a C permit (and certain other cases named in the guide)

A monthly payslip is not standardised by ESTV the same way, but student employers in Switzerland typically mirror the same ideas: gross, employee AVS/AI/APG/AC (and accident insurance lines), net, and a line for impôt à la source when you are withheld.

Contribution percentages and withholding tariffs change. For withholding estimates, Vaud publishes Excel calculators on Personnes imposées à la source (files labelled for tax years, including 2026). Open the year that matches your payslip.

Source for field meanings: ESTV guide Form 11, from 2026

Second pillar (LPP / BVG) on student jobs

BSV, Prévoyance vieillesse dans la prévoyance professionnelle (page updated 5 Jan 2026):

Compulsory LPP applies to employees already subject to AVS whose annual salary reaches at least CHF 22,680 (entry threshold; same figure stated for 2025 and, via the AVS maximum-pension formula, for 2026).
Insurance starts with the employment contract, at the earliest from 1 January after the 17th birthday.
Until age 24, compulsory contributions cover death and disability only; retirement savings start from 1 January after the 24th birthday.
Groups not subject to compulsory LPP include, among others, self-employed people and employees on contracts lasting no more than three months.

Many short or low-hour student jobs stay under the annual threshold and show no ch. 10 line. Funds may offer more than the legal minimum (surobligatoire). Check your contract and first payslip with HR; do not assume every campus job has 2nd-pillar deductions.

What LPP and pillar 3a mean for you, and getting the money when you leave: see Swiss pensions: LPP and pillar 3a.

Tax context for student jobs in Vaud (short)

Foreign workers living in Switzerland without a C permit (Vaud names permits such as B, L, F, N, Ci) are generally subject to withholding on Swiss employment income. The employer deducts it and remits it to the canton.
Swiss nationals and C permits file ordinary returns (see Student tax).
Residence tax (taxe de séjour) billed via the landlord is not income tax. See Residence tax vs income tax.
AVS student minimum contributions invoiced by the Vaud compensation fund are a different topic from payroll deductions on a job; see AVS (leaflet 2.10 amounts dated there). EPFL’s public AVS page also mentions student minimum contributions but is not the place for dated federal leaflet figures.

If the withholding line on your slip looks wrong, Vaud explains how to request a decision or a new calculation by 31 March of the year after the payment year (wrong gross, wrong annualising rate, wrong tariff). That is not the same as a full ordinary subsequent assessment (TOU). Details: same ACI withholding page.

ACI withholding contact on that page (Lausanne / West Lausanne office): Rue Caroline 11bis, 1001 Lausanne · 021 316 20 65 · info.aci-source(at)vd.ch (complaints must follow the postal rules stated there).

Quick checklist

Find your 756… number on the LAMal card, or ask school / employer / commune.
When you start a job, check the first payslip: AVS number, hours/gross, social deductions, impôt à la source if you have no C permit, and whether a 2e pilier line appears.
Keep monthly slips; request the annual Form 11 certificate when the year ends or when you leave the job.
Do not confuse AVS number, ACI taxpayer number, and residence tax.
Work-hour and permit rules: Working while studying.

Sources

Unofficial student project. Confirm figures on ESTV / ACI / your payslip; this page is not a rate table.