You can easily calculate the average of per day/month/quarter/hour in excel with a pivot table as follows:

1. Select the original table, and then click the Insert > PivotTabe.

2. In the opening Create PivotTable dialog box, check the Existing Worksheet, then put the cursor into the Location box and select a cell where you want to locate the Pivot Table in current worksheet, and click the OK button. See screenshot above:
Note: If you want to place the pivot table into a new worksheet, you can check the New Worksheet option in the Create PivotTable dialog box.

3. In the PivotTable Field List pane, drag the Date/Time field from Choose fields to add to report box to the Row (or Row Label) box, and drag the Amount field to the Values box. See screenshot:

4. Right click any date in the PivotTable, and then select the Group from the right-clicking menu. See screenshot above:

5. In the opening Grouping dialog box, click to highlight the item you want to calculate averages based on in the By box, such as Months, and click the OK button. And then in the pivot table, right click the Sum of Amount > Summarize Values By > Average. Now you will get all averages of each month in the Pivot Table, see below screenshots:

Supposing you have a hourly records table as below screenshot shown, but you need to calculate daily averages from the hourly records, how to solve it in Excel? Kutools for Excel's To Actual utility and Advanced Combine Rows utility also can help you.

1. Select the time cells that you will average by, and click the Home > Number Format box > Short Date to change the date & time to dates only.

Note: For calculating average by weeks/month/years, you can change the normal date&time to day of weeks/months/years only with Kutools for Excel's Apply Date Formatting feature and To Actual feature.

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2. Select the data range, and click the Kutools > Content > Advanced Combine Rows.

3. In the opening Combine Rows Based on Column dialog box, please select the Date/Time column in the Column list, and click the Primary Key, select the Amount column and click the Calculate > Average, at last click the Ok button. See screenshot:

Then the daily averages are calculated at once.

Note: This method also enables to calculate monthly/yearly average if you can show dates as months or years in the first step. By the way, Kutools > Format > Apply Date Formatting can show date as weekday, month, year, or other specified date formatting, and then change the dates to months/years with Kutools > To Actual.

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