Because the mailto link use several pieces of information, it must be assembled with concatenation.
The formula is bit tricky. While the ampersand is the operator for concatenation in Excel, it is also used to delimit the mailto link parameters (cc, bcc, subject, etc.). This means that some ampersands (&) are used to join text in the formula, and some are embedded in the final result. In the code below, the ampersands in yellow are used for concatenation in Excel. The white ampersands are embedded in the final result:
For the sake of simplicity, the formula above does not try to exclude empty parameters from the final result. In quick testing with Gmail and Outlook, missing parameters seem to be handled ignored gracefully. The behavior of other email applications may vary.
The Excel HYPERLINK function returns a hyperlink from a given destination and "friendly name". You can use HYPERLINK to construct a clickable hyperlink with a formula. The HYPERLINK function can build links to workbook locations, pages on the...
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.