> For the complete documentation index, see [llms.txt](https://formulapro.shadebridge.com/formula-pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://formulapro.shadebridge.com/formula-pro/formula-pro-custom-functions/custom-functions-overview.md).

# Overview

Formula Pro extends Excel-compatible formulas with **40+ custom functions** designed for monday.com workflows. These functions handle:

* **Dates & timelines** — monday.com date formats, timeline columns, working days
* **Mirror columns** — Condition checks across mirrored values from connected items
* **Text & regex** — Pattern matching, replacement, and formatting
* **Control flow** — Skip/ignore items, clear values, conditional projection

## Function Categories

| Category                                                                      | Functions                                                                                      | Use Case                                              |
| ----------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------- | ----------------------------------------------------- |
| [Date & Time](/formula-pro/formula-pro-custom-functions/date-time.md)         | ADD\_DAYS, SUBTRACT\_DAYS, WORKDAYS, FORMAT\_DATE, HOURS\_DIFF, etc.                           | Date arithmetic, formatting, working-day calculations |
| [Timeline](/formula-pro/formula-pro-custom-functions/timeline.md)             | TIMELINE, TIMELINE\_FROM\_DATES, START, END, DATES\_FROM\_TIMELINE                             | Timeline column parsing and construction              |
| [Text](/formula-pro/formula-pro-custom-functions/text.md)                     | CONTAINS, REGEXREPLACE, REGEXTEST, TEXT                                                        | Pattern matching, regex replace, formatting           |
| [Math](/formula-pro/formula-pro-custom-functions/math.md)                     | ADD, MINUS, MULTIPLY, DIVIDE, RAND\_BETWEEN, comparison operators                              | Arithmetic with string concatenation support          |
| [Value Checking](/formula-pro/formula-pro-custom-functions/value-checking.md) | COALESCE, HAS\_VALUE, VALUE\_EXISTS                                                            | Null handling, value presence checks                  |
| [Mirror](/formula-pro/formula-pro-custom-functions/mirror.md)                 | ALL\_MIRROR\_VALUES\_MATCH\_CONDITION, AT\_LEAST\_ONE\_MIRROR\_VALUE\_MATCHES\_CONDITION, etc. | Mirror column condition evaluation                    |
| [Control Flow](/formula-pro/formula-pro-custom-functions/control-flow.md)     | IGNORE, SKIP, PASS, CLEAR, EMPTY, SWITCH                                                       | Skip items, clear values, conditional logic           |

## Naming Conventions

* Functions are **case-insensitive** — `ADD_DAYS` and `add_days` are equivalent
* Most functions follow `FUNCTION_NAME` style
* Aliases exist for common operations (e.g., `PLUS` = `ADD`, `MIN_DATE` = `DATE_MIN`)