For me, it's like 4 or 5 months because when I started learning the rules of chess, my rapid rating was around 1400, and now it's 1840. For my puzzles, I went from 800-2101 in 2 or 3 months.
How long did it take you to get to an 1800 rating?

With the recent changes to both rapid (10 minutes, the most played time control, is now rapid, so a huge change) and bullet (literally boosted everyone's rating), I'm still not sure how to evaluate those ratings on chess.com anymore.
If you have talent for chess it takes little time.
If you have absolutely terrible chess skills, you will never get there.
Everyone is different.

I could have gotten there earlier, but I slacked off for a while.
You've also averaged over 400 games a month + 400 puzzles a month + 40 lessons a month for the last year and a half... just so beginners who are "slacking off" playing 20 games a month wont expect similar results.

I would say 2 years probably if you are not going tryhard but are putting in time here and there. Those that say they got to 1800 in 1 month probably used some engine help, not trying to bash them, just being realistic.

I could have gotten there earlier, but I slacked off for a while.
You've also averaged over 400 games a month + 400 puzzles a month + 40 lessons a month for the last year and a half... just so beginners who are "slacking off" playing 20 games a month wont expect similar results.
I mean I stopped playing frequently after I hit 1600... Went up to 1790 but declined back to 1690 over the span of a couple months, all the way to march 2020.

Even if they played as much they probably wouldn't improve as fast, but I thought it was worth pointing out because (at least AFAIK) most new players don't play that much.
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FIRST TOURNAMENT I EVER PLAYED. FIRST USCF GAME I EVER P;LAYED I WAS UNRATED AND PLAYED BLACK AGAINST AN EXPERT. AFTER THE GAME WAS OVER----- SOMEONE SAID "YOU JUST BEAT THE CHAMPION OF PUERTO RICO!"

I think I got pretty close to 1800 blitz a couple weeks ago (1791), and this is after around 6 months of playing chess continuously. I began from around 1200 blitz on chess.com (although I played on Lichess for a month beforehand and was rated at approximately 900). So, in general, if you are truly interested in chess and are willing to study, I'm guessing that it will take you a little more than half a year. On the other hand, if you are terrible at chess it may take you years or you'll simply never get there.
This is for beginners aspiring to get to 1800 and those interested in data. How long did it take you to get to an 1800 rating on Rapid, blitz or bullet. For me it took about a year to get from 900 to 1800.