This formula uses the named ranges "dates" (B5:B25) and "durations" (D5:D25). Durations column D are in minutes, calculated by subtracting the date opened from date closed.
The AVERAGEIFS function is designed to average ranges based on multiple criteria. In this case, we configure AVERAGEIFS to average durations by month using two criteria: (1) matching dates greater than or equal to the first day of the month, (2) matching dates less than or equal to the last day of the month.
To bracket dates by month, we use a simple trick to make things easier: In column F, instead of typing month names ("Jan", "Feb", Mar", etc.) we add we add actual dates for the first of each month (1/1/2016, 2/1/2016, 3/1/2016, etc.),. Then, we use the custom date format ("mmm") to display the month names.
This makes it a lot easier to build the criteria we need for AVERAGEIFS using values in column F. To match dates greater than or equal to the first of the month, we use:
To match dates less than or equal to the last day of the month, we use:
We get the EOMONTH to return the last day of the same month by supplying zero for the months argument.
Note: concatenation with an ampersand (&) is necessary when building criteria based on a cell reference.
Pivot Table solution
A pivot table is an excellent solution when you need to summarize or average data by year, month, quarter, and so on, because pivot tables provide controls for grouping dates automatically. For a side-by-side comparison of formulas vs. pivot tables, see this video: Why pivot tables.
If you need to sum if by year, you can use the SUMIFS function with two criteria. In the example shown, the formula in H6 is: = SUMIFS ( amount , date , ">=" & DATE ( G6 , 1 , 1 ), date , "<=" & DATE ( G6 , 12 , 31...
To sum by month, you can use a formula based on the SUMIFS function, with help from the EOMONTH function. In the example shown, the formula in F4 is: = SUMIFS ( amount , date , ">=" & E4 , date , "<=" & EOMONTH ( E4...
To average by month, you can use a formula based on the AVERAGEIFS function, with help from the EOMONTH function. In the example shown, the formula in F4 is: = AVERAGEIFS ( amounts , dates , ">=" & F5 , dates , "<="...
The Excel AVERAGEIFS function calculates the average of numbers in a range that meet one or more supplied criteria. The criteria in AVERAGEIFS supports logical operators (>,,=) and wildcards (*,?) for partial matching....
The Excel EOMONTH function returns the last day of the month, n months in the past or future. You can use EDATE to calculate expiration dates, due dates, and other dates that need to land on the last day of a month. Use a positive value for...
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.