I’ve heard that the optional Harvard supplement should be under a page in length (~650 words). However, mine went above that limit and was ~730 words. How long was each of your guys’ optional supplement?
This from several years ago: http://www.thecrimson.com/article/2011/11/15/common-app-new-word-limit/
Yet another perspective
I guess the take-a-way is: don’t go over the 650 word limit of Common Application for your additional essay unless you absolutely, positively need the extra words to convey your point. And remember the adage: less is more.
FWIW: I personally think students write too much exposition; often times essays are much better when a student deletes the first paragraph of their essay – and sometimes the first and second paragraphs of their essay – and just jumps right in and punches it.
I chose the booklist and it was somewhere on the order of 3-4 pages because that was seriously just the list of stuff I had read. It didn’t specify any sort of length requirement so I did not feel the need to truncate it, and since it’s not as easy for a list to wear out its welcome as purple prose and unending exposition I didn’t think much of it.
OP, you’ll be fine. that much of an overspill will not make or break the app; any length is good if the content is worthy!
I reflected on an experience I had had and it was probably a page and a half.
My S’s essay is 600 words about an experience.
mine was around 730 words too. they didn’t specify a word range on the application, so i think you’re fine 
Mine was 1100+
My D’s was about 500 words - in a bullet point format. She used her Stanford essay about a future roommate and cut it down.
@carlson2 The Stanford essay is max 250 words though — how can you “cut down” a 250 word essay into a 500 word one?
@VenomBuds. I misspoke. She took her Stanford essay and added to it. She initially did not want to use her Stanford essay for H, but was running out of both time and energy.