# MS-Excel - Functions and Formula Tutorials

## Turn Conditional Formatting and Data Validation On and Off with a Checkbox

Data validation can make it far less likely that a user will accidentally enter incorrect data. Sometimes, you might need to make it easier to enter data that otherwise would be flagged as incorrect. Read more...

## Count or Sum Cells That Meet Conditional Formatting Criteria

Once you can see the results of conditional formatting, you might want to create formulas that reference only the data that was conditionally formatted. Read more...

## Identify Formulas with Conditional Formatting

Once a formula is entered into a cell, you can tell whether the cell is a static value or a value derived from a formula only by clicking in each cell and looking in the Formula bar, or by pressing Ctrl-~ (tilde). This tutorial fills that gap with a custo Read more...

## Formulas that Reference Other Workbooks

Excel formulas get pretty complicated when a mega-formula references another workbook. Read more...

## Construct Mega-Formulas

Mega-formulas-a formula within a formula, within a formula-are enough to send even the most seasoned Excel veteran running for the hills. Read more...

## Determine the Number of Specified Days in Any Month

When you're creating calendar-related applications, especially payrollapplications, you sometimes need to know how many times a given day of the week appears in a particular month. Read more...

## Show Total Time As Days, Hours, and Minutes

When you add hours in Excel, you can have the result return as total hours and minutes, but unfortunately, not as days, hours, and minutes. Displaying that will take some extra work. Read more...

## Use the VLOOKUP Function Across Multiple Tables

Although VLOOKUP itself is very handy, it is restricted to looking in a specified table to return a result, which sometimes is not enough. You can escape this limitation with the INDIRECT function. Read more...

## Return the Weekday of a Date

This tutorial shows how to extract the weekday of any date by using the WEEKDAY function. Read more...

## Find the Last Day of Any Given Month

Dates can tricky to work with, and finding the last day of a given month can be a challenge. Read more...