How does reading increase your vocabulary?

It may be that some people increase their vocabulary by working through a page of the dictionary every day. That might work for them. It would be too much of a chore for others.

The best way to increase your vocabulary is just to read.Read, read and read. That's the way you have increased your vocabulary up till now. When you learned to read in Grade Two or Three in school that was it. None of your later teachers taught Reading. You improved your reading by reading yourself. It's a simple plan.

So you are reading a book, or a magazine, or a newspaper. (Not too difficult, just a normal one that suits your level of reading.) As you go along, you come across a new Word. Aha! Do you stop and look it up in a dictionary? Not usually. Instead you hazard a guess as to its meaning, from its context. And you read on. The Word will probably appear again soon, in a slightly different context, so you can refine your understanding of what it means. (This is all done usually subconsciously, and it all happens in a flash!) If it's a crucial Word to the story, then it will appear again. And by the end of your reading, you have a better understanding of that Word.

And next time you meet it you will get a chance to refine its meaning again, until it's quite clear what it means.

So read. Read! Read! Because Reading just automatically, painlessly and effortlessly improves your vocabulary.