Fit verb followed by in preposition

Question

I have a question regarding the usage of the verb "fit", especially when followed by the preposition "in". Now I am aware that there is a "fit in" (as in to become assimilated in a group) idiom but this is not the usage that I have a question on.

Could you please help me know when to use the "in" preposition in a regular "fit" scenario?

1. There are several instances where the fit verb does not require the "in" preposition:

• Does the new meeting time fit your schedule?
• The concert tickets didn't fit my budget

2. The Free Dictionary has some samples under the "idioms" category for fit in, where they use the "fit" verb in the same sense in which I am trying to use it. Their definition is:

To be able to be placed within something because there is sufficient space.

However their example then proceeds to use "into"

Do these papers fit into that file? I know it's practically bulging at the seams.

3. Cambridge dictionary came up with a better example:

How many people can fit in your car?

In this last scenario I understand that removing the "in" and just saying that something "fits" my car, turns the meaning into something that "goes well" or "looks good" with the car, therefore I guess this is why they use the "in" preposition.

So I am very confused because I cannot understand when to use "fit" followed by "in"

Answer 1

Welcome to EL&U, Luis. The difference between fit in and fit into is very subtle and, in practice, the two terms are almost synonymous. In so far as a difference exists it relates to the difference between something occupying a space (fit in) and something being inserted into that space (fit into).

For example, in the case you give of the people and the car when we say "How many people can fit in your car" we are referring to the number of occupants who can travel in it. Obviously those people have to fit into the car before they can travel but we are concerned about the safe and comfortable occupancy for journeys. In fact more people can fit into the car than can fit in and travel and there used to be a rather silly Guinness world record for the number of people who could fit into an old style BMC mini. However the car could never travel with that number of occupants.

When it comes to inserting furniture into rooms the two terms are almost interchangeable. For instance we can say either "I will buy the smaller wardrobe, it will fit in the alcove in my bedroom" or "I will buy the smaller wardrobe, it will fit into the alcove in my bedroom" and either sentence is equally acceptable. However it would be slightly less common to say "We managed to fit the wardrobe in the alcove" than "We managed to fit the wardrobe into the alcove" because we would be talking about the process of inserting the wardrobe into the space rather than the wardrobe occupying the space but both terms are used in practice.

The reason that the papers are described as fitting into the file in your example is that the speaker is talking about the process of adding the new papers to the contents. If we were talking about choosing a file for some papers we might say "Those papers are US letter size, they won't fit in that A4 file because they are a bit too long." In that case we would be thinking about the physical constraints but fit into might still be used.

The more definite difference is between something that fits in/into a space and something that fits onto/on or just fits. For instance "Will those alloy wheels fit onto (or just fit) my car. Wheels fit on the outside, not the inside of a car and the preposition needs to reflect the that reality.

Answer 2

The verb fit is used with many senses (see Merriam-Webster or OED), as John Lawler mentions in his comment, describing the radiating broadenings from the central adjectival sense well-articulated; in good working order to transparent (fit into a place [in a well-ordered fashion]) and then opaque idioms.

Different subsenses behave differently. I'll just cover the ones mentioned in the question, using the Lexico definitions and examples [text re-ordered and amended slightly]:

fit [verb] fits, fitting, fitted [UK] / fit [US] ...

• [with object] ...

(3) Be compatible or in agreement with; match.

• The landlord had not seen anyone fitting that description.

• Fast, simple and delicious, these dishes can be adjusted to fit your schedule, grocery list and occasion. [mixed usage]

• She has adjusted her services to fit the customer's budget.

(3.1) Be suitable or appropriate for.

• The punishment should fit the crime.
• Fast, simple and delicious, these dishes can be adjusted to fit your schedule, grocery list and occasion. [mixed usage]

[Notice that these all take a direct object: no preposition.]

fit ...

(1.2) [no object, with adverbial of place] Be of the right size, shape, or number to occupy a particular place.

• Fiona says we can all fit in her car.
• The shape of the carton fits more conveniently into home freezers.
• Science doesn't usually fit neatly into categories of all good or all bad.
• Cut the slices of bread to a size that will fit inside your soup bowls, and toast them until dark brown ....
• Drain the water and set the spears on a plate, and cut them to size so they can fit on top of the muffins.
• Picking the strategy that best fits into your schedule will help you maintain optimum weed management.

[Note that all these examples need a locative/directional (Lexico has 'adverbial of place'). All the examples given here use classical prepositional phrases, not limited to in-phrases and into-phrases. Locatives/directionals such as 'here', 'inside' are also possible.]

Notice also that

1. Subsenses overlap ('compatible with' and 'appropriate for')
2. With 'schedule' say, 'fit' {and 'fit with'} (be suitable/appropriate for), and 'fit into' (can easily be slotted into) are both idiomatic.