Can anyone help with a formula to count the number of times a character appears in a cell e.g. if the word Mississippi was in the cell, I want to count the number of times the letter 's' appears and would expect the formula to return the value 4.

My spreadsheet has cells containing text with up to 92 characters and I'm looking to count commas before splitting the text but I have over 200,000 rows of data with varying lengths of data, some with commas and some without.

Thanks,
Alan