In Canada, unlike in many states, there is no concept of employment "at-will". Instead, the general rule, in the absence of a contractual term to the contrary, is that an employee can be terminated summarily, without notice, for just cause or, in the absence of just cause, upon being provided with reasonable advance notice of termination or pay in lieu of notice at common law.
As a sidebar, because the period of reasonable notice at common law can be significant, depending on the circumstances, employment agreements or letter of offers will often contain termination provisions that limit the entitlement to notice or pay in lieu of notice to something that is less than the employee would obtain "at common law". The Supreme Court of Canada in Matchtinger v. HOJ Industries Ltd.  1 S.C.R. 986 considered the circumstances under which a contractual term will be enforced.
Let's say there's no contract dealing with termination, the question is how do we go about determining the period of reasonable notice for the employee?
The most often cited case in this area is Bardal v. Globe & Mail Ltd. (1960), 24 D.L.R. (2d) 140 which contains the following quote:
There can be no catalogue laid down as to what is reasonable notice in particular classes of cases. The reasonableness of the notice must be decided with reference to each particular case, having regard to the character of the employment, the length of service of the servant, the age of the servant and the availability of similar employment, having regard to the experience, training and qualifications of the servant.How is this helpful? Well, the older, more senior, longer service employee will, all things being equal, be entitled to a longer period of reasonable notice than a short service, junior, younger employee.
But what is the period of notice, isn't there a formula that we can apply to determine the period of reasonable notice at common law? The short answer is "no". We hear talk of the "month per year of service" rule. I can't count the number of times that I have had this quoted to me by plaintiffs counsel. My response: There is no such rule! Don't take my word for it, look at what the Ontario Court of Appeal said about it in Minnott v. O'Shanter Development Company Ltd. (January 7, 1999, Ont. C.A.):
 The rule of thumb approach suffers from two deficiencies: it risks overemphasizing one of the Bardal factors, "length of service", at the expense of the others; and it risks undermining the flexibility that is the virtue of the Bardal test. The rule of thumb approach seeks to achieve this flexibility by using the other factors to increase or decrease the period of reasonable notice from the starting point measured by length of service. But to be meaningful at all, this approach must still give unnecessary prominence to length of service. Thus, in my opinion, the rule of thumb approach is not warranted in principle, nor is it supported by authority.So where does this get us? Simply put, there is no magic to determining the period of notice and there is no secret formula that lawyers simply apply in giving their clients advice. You read hundreds of cases, you look at the Bardal factors, and others that come into favour having regard to the circumstances, and you give the client a range of what you believe would likely result if the employer were sued and the judge had to determine the period of reasonable notice.
To the frustration of many clients, there is no science to this (unless inexact science counts). Largely, it's an assessment of a range based on experience. So when you call your lawyer, you should probably have the following things available among others:
- Does the employee have an employment agreement or letter of offer?
- What is the employee's position?
- What is the employee's age?
- How long has the employee been employed?
- What is the total compensation (salary, bonus, car, stock options etc.)?
- If there are documents relating to compensation matters, they should be available.
- What are the circumstances surrounding the hiring (particularly of a short service employee)?
- What are the circumstances surrounding the termination?