Sometimes, especially when you work with a lot of data, you need to transform it. If you need to convert some range of data by dividing or multiplying it, it can be done in Excel in two clicks:
Use COUNTIF if you need to sum values for a particular person or another criterion.
Use SUMIF if you need to sum values for a particular person or another criterion.
You can usually view formulas in an Excel cell when the cell is selected, but you can protect a spreadsheet by hiding the formulas in some cells.
Often you'll want to insert a series of dates into a worksheet. The most efficient way to enter a series of dates doesn't require any formulas - just use Excel's AutoFill feature.
The Solver tool allows you to specify multiple adjustable cells and constraints on the values that the adjustable cells can have, generate a solution that maximizes or minimizes a particular worksheet cell, generate multiple solutions to a problem.
Goal seeking is a useful feature that works in conjunction with your formulas. If you know what a formula result should be, Excel can tell you which values of one or more input cells you need to produce that result.
Because timestamps are represented as serial numbers, you can subtract the earlier time from the later time
to get the difference.
When calculating the difference between two dates, you may want to exclude weekends and holidays.
You can easily count the number of unique values of the range using a simple formula.