Note the left side of the range reference is locked ($B$5) and the right side is relative (B5). This is called a "mixed reference", since it contains both absolute and relative addresses, and it creates an expanding range.
As the formula is copied, the first cell in the reference is locked, but the second reference expands to include each new row. On each row, COUNTIF counts cells in the range that are equal to "blue", and the result is a running count.
The outer layer of the formula uses the IF function to control when COUNTIF fires. COUNTIF only generated a count when the value in B is "blue". If not, IF returns an empty string ("").
Running count of every value
To create a running count of every value that appears in column A, you can use a generic version of the formula like this:
To count the number of cells that contain certain text, you can use the COUNTIF function. In the generic form of the formula (above), rng is a range of cells, txt represents the text that cells should contain, and "*" is a wildcard matching any...
To calculate a running total, you can use the SUM formula with a mixed reference that creates an expanding range. In the example shown, the formula in cell D6 is: = SUM ( $C$6:C6 ) When this formula is copied down the column, it correctly reports a...
COUNTIF is a function to count cells that meet a single criteria. COUNTIF can be used to count cells with dates, numbers, and text that match specific criteria. The COUNTIF function supports logical operators (>,...
Excel Formula Training
Formulas are the key to getting things done in Excel. In this accelerated training, you'll learn how to use formulas to manipulate text, work with dates and times, lookup values with VLOOKUP and INDEX & MATCH, count and sum with criteria, dynamically rank values, and create dynamic ranges. You'll also learn how to troubleshoot, trace errors, and fix problems. Instant access. See details here.