I have a spreadsheet with column H = date and column J is a numerical
value. I am looking for a way to sum all entries in the last 90 days.

I've been using this formula that counts months but I want to go by
days to get a more accurage total.

=SUMIF(H:H,""&DATE(YEAR(TODAY()),MONTH(TODAY())-3,DAY(TODAY())),J:J)

Can anyone help me with this?

Jim