Robert Graves and Alan Hodge, in
The Reader Over Your Shoulder , offer this “scale of approximate counting”: one or two, two or three, a few, several, a dozen or so, a score or so, a dozen or two, a score or two, a few dozen, dozens, a hundred or so, a few score, scores, a hundred or two, a few hundred, hundreds, a thousand or so, etc.
So I’d think, abstractly, that a few might be three or four to six or seven.
Fewer than several .
But as Anderson Silva says, context is everything.
ell.stackexchange.com/users/32/StoneyB on hiatus
Here, xkcd explains words for small sets.
Source
ell.stackexchange.com/users/329/razpeitia
IMHO, there is no rule, it really depends on the context and what you are talking about.
For example: A few people in a studium watching a show, there could be dozens, even hundreds of them, while a few things in a backpack could be just 3 or 4.
Another example: Quite a few students from our high school go on to college.
Would you say it is less than 10?
IE, if it's not many , then it's a few .
Hope it helps.
ell.stackexchange.com/users/290/Androiderson
The way I always understood it was: For small amounts (e.g. less than 12) Where ONE was the number, then 'one' was the description.
Where TWO was the number, then 'a couple' (or even a 'brace') was the description.
Where THREE was the number, then 'a few' was the description.
When using this terminology, however, inexactitude was implied - therefore it could include FOUR or FIVE, but THREE would be the expected number.
I should note that where I am from (Ireland), the term 'a good few' would imply more again (even up to NINE or TEN) and indicate satisfaction with the number also.
This can be compared to the more generally used 'only a few', or 'few', which could indicate dis-satisfaction.
For larger amounts (e.g. stadia attendance) the rule of three could be adapted to fractions -
when only a third of the seats are filled, one could safely say the game was attended by 'few'.
Obviously context is vital here, as you are still talking about several hundred - even thousand - people.
You are not so much referring to how many were there, as demonstrating verbally how many were not . '
Few' in this instance is a negative term.
Another example of contextual usage would be in boxing or sparring, where someone would recieve or give 'a few' punches.
No actual number is implied here - in fact, only a very general impression is implied - but suggests how well or poorly a fighter did over the entirety of the match.
Therefore, to answer your question, the actual numerical range indicated is only done so when dealing with already small amounts, and would generally be accepted to contain at least three, but allow for four or five.
When using this term, inexactitude is a given and is indeed the primary implication when dealing with large numbers.
ell.stackexchange.com/users/331/Eamonn
It's relative to the context.
That context can be finite or infinite.
It is intuitively more than 1 (a border-line certainty)It
is fewer or less than some or several, and definitely not many.
I would say,In a finite context, it is intuitively less than a tenth of a whole.
in an infinite context, it is less than a tenth of what ever upper limit expressed.
ell.stackexchange.com/users/328/Brett Caswell
There is no exact quantification for the phrase "a few", since in general you are talking about a group, an amount of something
may it be big or small, the closest I think is, 50% of the average can cover "a few".
But then again this is not mathematically proven..
ell.stackexchange.com/users/342/mirageservo
When we use  a few , how many items are usually indicated? My intuition tells me it's something between 3 and 9, but what is the most common range for  a few ?
How many items are actually "a few items"?
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ell.stackexchange.com/users/3/Danubian Sailor
It would generally be accepted to contain at least three, and a few may be three or four to six or seven.  There is no rule,  and it really depends on the context and what you are talking about. It depends on context, though the range may be between three and seven.
The range may be between three and seven. It depends on context.