This is probably the stupidest question ever.. But I have a large spreadsheet, linked from multiple other sheets.

Column a is the vendor, category-then the rest of the column are the months in a year, and the last row is sum for the year by that vendor

Now when I sum that last column (the Vendor total by the end of the year)-vertically I get $241,765.43

On the very bottom, There's a sum for each month, all vendor, no matter the vendor-and sum horizontally through this total line and receive $284,387.54.

Hope I explained this well!

They're summing the same exact information. So why is it different.

I've spent all day frying my eye balls, double checking each link, formula, and everything is as it should be.

In another places, I sum this same data again, using a sumif by the Category for the criteria and the yearly Total for the sum range.

I then summed all the categories, and it matches the $241,765.43

But I Don't understand why the horizontal summation is Completely different. All the formatting for dates, categories, totals etc match.