If you first became eligible for your HSA after the beginning of the year, then you are allowed to contribute up to your annual maximum for that year without any proration. This is called the “Last Month Rule” and it means that you have until December 1st of the year in which you first become HSA-eligible to still contribute 100% of your maximum contribution for that year. You can also just give a prorated contribution if that's better for you.

Did this answer your question?