This is a bastardization of a nautical phrase.

Problem:
The word “in” is incorrect in this phrase.

Explanation:
The Phrase Finder has a complete explanation of the correct phrase, which is “by and large”, not “by in large”.

Here are the highlights from that superb explanation of “by and large”.

Regarding “large”: The wind is said to be “large” when it is blowing behind a ship’s travel direction.

For example, if you want to sail to the east and the wind is coming out of the west, then “large” is the correct label for the wind.

Regarding “by”: In contrast, to be “by the wind” is to be facing into the wind.

Although many non-sailors see this as a sailing disadvantage, the physics of sailing show that it is advantageous to sail into the wind.

So being able to sail “by and large” means being able to sail not only downwind (the “large” part) but also into the wind (the “up” part).

This explains why the phrase means on the whole.

And one can understand how “by in large” resulted from a lack of understanding about this nautical phrase and a misinterpretation, upon hearing it, of the conjunction “and” as the preposition “in”.

For fun, I searched Google for each of the following (with the quotation marks, to avoid variations) and got about the indicated numbers of matches:

• “by and large” — with the conjunction “and” — 5,090,000 matches
• “by in large” — with the preposition “in” — 44,400 matches

This tells me that Web authors have used the correct “by and large” versus the incorrect “by in large” by a ratio of 115-to-1, which is excellent.

Solution:
“by and large”