Hi @hoiki426
You can build it into a formula tool using something like this as a reference to the calculation https://corporatefinanceinstitute.com/resources/excel/functions/mduration-function/
You also have the ability to add formulas that you want via Formula Addons. A more complete add on example from @jdunkerley79 is the Formula Add ons here: https://github.com/jdunkerley/AlteryxFormulaAddOns
Happy to add a MDURATION to the library
Have been thinking some daycount functions make sense as well