Calculating your seniority: why every agreement does it differently

In a unionized workplace, seniority is one of the most important notions — and one of the most misunderstood. It decides:

• your turn in vacation picks;
• your priority on a job posting;
• your protection in case of layoff;
• your rank on recall;
• sometimes your step or your seniority premium.

And yet, two agreements can describe "10 years of seniority" in radically different ways. Here's the user manual.

Seniority vs. service: the difference

First, distinguish two notions often confused:

• Service (or "length of service") = time elapsed since your hiring, in calendar years.
• Seniority = what the agreement grants you, by its own rules.

Seniority is not always equal to service. It can be less (if some periods don't count) or more (if the agreement "banks" extra at certain occasions).

The two main calculation methods

1. Seniority in hours/days worked

Many agreements calculate seniority in hours actually worked (or days actually worked). It's typical of sectors with variable schedules: hospitality, retail, some construction trades, warehousing.

Consequence: if you're part-time, you accrue seniority more slowly than a full-time colleague. Conversely, if you work a lot of overtime, some agreements count it in seniority (others don't).

2. Seniority in years (hire date → current date)

For fixed-schedule jobs (health care, education, public service, many manufacturers), it's often the hire date that serves as the anchor, and seniority accrues in calendar years (sometimes in months/days, but without looking at hours).

Consequence: a 6-month unpaid leave may, or may not, interrupt your seniority, depending on what your agreement says.

Periods that count (or don't)

Your agreement generally specifies what happens during the following periods. This is where agreements differ the most.

Probation

Almost always: seniority accrues retroactively from hire, once probation is passed. The probation months are not lost.

Sick leave / short-term disability

Often counted in full, especially if the salary insurance plan takes over. Sometimes capped (e.g., "up to 12 consecutive months").

Parental / maternity leave

By default, since the Act respecting labour standards, seniority continues to accrue during a parental or maternity leave. Your agreement cannot go lower. It can go higher (e.g., also maintain your accrual of benefits).

Unpaid leave

This is the big variable. Some agreements:

• Fully maintain seniority during an unpaid leave (often up to 12 or 24 months);
• Suspend it (the leave time isn't counted, but you don't lose what you had);
• Provide a cap (up to X months it counts, beyond that it's suspended).

Layoff

For most agreements, seniority is maintained during a layoff — up to a certain time limit (often 12, 18, or 24 months). Beyond that, you may lose your recall right and your seniority.

Educational leave

Depending on your agreement, this can be treated as a regular unpaid leave, or have a specific regime (notably if the study is funded by a training fund).

Transfer, promotion, reassignment

Seniority is generally preserved during a transfer or promotion within the same bargaining unit. During a transfer to another unit or another employer (e.g., merger, acquisition, administrative transfer), the rules vary depending on the agreements.

What seniority actually does for you

Vacation choice

Almost every agreement provides that vacation is chosen by order of seniority, on a fixed posting period.

Consequence: knowing your rank means knowing whether you'll get your two weeks in July or not.

Job posting

When a position opens, the posting procedure often gives priority to employees with the most seniority among qualified candidates. The exact rule ("qualified AND most senior" vs. "most senior of the qualified") varies — and makes a difference in practice.

Layoff and recall

The classic rule: layoffs go to the least senior, and recalls go to the most senior first. But your agreement may provide for caps by job class, versatility rules, exceptions (essential positions protected).

Salary step and progression

Some agreements directly link your step to your seniority (one step per year of seniority). Others distinguish seniority (rank) from service (step).

Seniority premium

Some agreements provide a lump-sum premium or salary increase past a certain number of years (e.g., +2 % after 10 years). Check your salary appendix.

How to find your exact seniority

Here's the process:

1. Request your seniority statement from your employer or your union. Most agreements require an annual or semi-annual posting.
2. Check the reference base: seniority in hours worked, or in hire date? On what basis?
3. Check non-counted periods if applicable (unpaid leaves, periods outside the union, etc.).
4. Compare with colleagues in a similar situation — unexplained gaps are a warning signal.

In case of disagreement about your seniority

A few common scenarios:

• You believe you have more seniority than what's posted;
• A period wasn't counted;
• You were hired on an earlier date but formalized later;
• A merger or transfer scrambled the calculation.

The steps:

1. Document your arguments: contracts, pay stubs, hire letters, witness statements.
2. Talk to your steward before any official contestation.
3. If justified, the union can file an interpretation grievance to correct your rank.

Watch the deadlines: a disagreement on posted seniority often has to be contested within a short time of posting (sometimes 30 days).

Costly traps

• Resigning and returning: almost always fatal for seniority. You restart from zero, except in exceptional provisions.
• Refusing a recall after layoff: can cause you to lose your recall right and eventually your employment relationship and seniority.
• Accepting a transfer to a position outside the unit without clarifying what happens to your seniority: the default rule may make you lose all your years.
• Not checking the annual posting: if an error slips in and you don't contest it within the deadline, it "crystallizes."

The bottom line

Seniority is your union capital. It builds up slowly, can be lost quickly, and conditions a large part of your comfort at work.

Read the "Seniority" article of your agreement. Do it once, calmly, identifying the periods that count, the exclusions, and the exact calculation. Then check your annual statement.

That's 30 minutes of reading that can earn you years of peace of mind.