I have a compensation worksheet that lists each employee's compensation by
month. So column A is the name and the next 12 columns are Jan - Dec showing
their monthly gross salary.

I have another section of the worksheet that shows name in column A and then
social security costs in each of the next 12 columns. I need a formula that
will calculate the YTD social security costs up to the IRS limit. For
example, if social security (6.2%) is assessed on the first $106,000 - i need
the formula to look at YTD earnings and if it is over that limit - the amount
will be zero.

that part is simple. however what happens in the month where the earnings
first exceed the $106,000? Say year to date earnings from the prior month
are $104,000 and the current month earnings are $108,000. I need the formula
to calculate social security for only the $2,000 and not the entire
compensation for that month.

Any help would be greatly appreciated. Thanks!