I think I have accrued 1 day overstay on an F1 visa in the USA, beyond the 60-day grace period. Different online tools give different results. My 60-day grace period began on October 24th, 2017 (date on document) and I left on December 23rd 2017. I thought it was 60 days. I'm confused.
How does USCIS calculate the grace period?