What is minimal acceptable font size you should use when building your resume outside of legal note? I would like to avoid expanding beyond 2 pages.
You should stick to a standard page layout, so no less than 10, probably slightly bigger to improve readability.
The point of keeping your resume brief, is to limit the amount of information that the person reading it will need to process. To do so, tailor the CV to the position and include only the details that are relevant to the position you are applying for. Some old or small experiences could be aggregated in a single item or even omitted.
Reducing the page count by shrinking the font and margins will make it harder to read on top of it being long. That is worse than using an extra page.
Seems that you commented:
It is already super cut down version. I just had 8 jobs so even few lines about each makes it 1-2 pages.
It is important to remember that you should tailor your resume to better fit the job position you are applying for. This means that you should prefer including relevant highlights of your profile that would be of interest to those specific recruiters, or that would be valuable in the role you want to fulfill.
You should also refrain from including not so relevant information that could lessen the positive impact your relevant features may have.
I'd say that if one has had several jobs in the past, including all of them could take away valuable space on your resume. I suggest you include only your most recent jobs or those that are related to the job you seek, and try to leave the other out (or just list them or mention on a paragraph, without going into much detail).
This will give you extra space for interesting stuff that can boost your application.
Not a direct answer, just a suggestion that the "unbreakable" 2-page rule might not be.
With *cough* decades of experience, I have managed to keep my CV down to 6 or 7 pages (12 point font). I have never had anyone complain of the length, and have no trouble landing contracts.
I got it down to 6 or 7 pages by leading with a summary, so that I don't need to repeat it on every job, and a cut-off about 10 years back, with "further details available on request".
It's tricky to judge. Some might say that experience 10 years ago is stale, but if it reinforces more recent experience and underlines my subject matter knowledge, then I think it germane.
One thing that I have never heard anyone discuss is how prospective readers will know that it is longer than 2 pages. I can't remember the last time that I got a CV from a prospective candidate which was not in electronic form.
That means that someone reading my CV reads the summary, and is either hooked, or moves on to the next guy. If hooked, he can read further and stop whenever he has read enough to convince him. If we wants to know lots, he can read to page 6 or 7; or he might just read the summary and the two recent jobs.
But he's not going to know that my CV is is 6 or 7 pages long unless he reads that far, and by that time it's too late to reject it for being too long.
Just stating what works for me. YMMV
To directly answer the question - which no one has done yet.
Stick to a minimum of 10 Point
Anything less risks being hard to read to read and you can't assume that every reader has 20/20 vision and you risk getting your cv discarded especially if its being read by an older person
Don't get to hung up on exact numbers about the number of pages in a cv there is no magic trick here.
In my experience, I would never recommend going past 2 pages.
I have many friends in the HR field and most won't read past page one. My suggestion to you is don't go crazy small with the font (keep it at 11 or 12) and stick with a standard page layout.
I would recommend that your attention is better spent by focusing on only including the important content and wording your message in such a way that the critical items are on page one.
If you send out a resume with tiny fonts I can assure you it will go straight in the bin. You aren't making yourself more appealing by making your resume more difficult to read. You are doing the opposite. You can reduce the amount of information for jobs you worked that are older than, say, 2 years. Most people don't care all that much about what your daily duties were 10 years ago using technologies that are no longer relevant.
Never go below 10 and don't be so concerned with length.
A resume needs to be as long as it needs to get the attention required to get you an interview.
Personally, I would rather read a 4 page resume in a good sized font (12) than a two pager at 8.
Remember, a resume has just one purpose to GET AN INTERVIEW never sacrifice legibility to keep the length down. People reviewing resume's get plenty of qualified applicants. if your resume is difficult to read, it won't be read.
If you have to make a choice between adding an extra page, or shrinking the font, ALWAYS ADD THE EXTRA PAGE