Dynamic PDF fields

I am recreating a PDF form that my institution has. It is to report mileage for reimbursement. What I am trying to do is make certain fields dynamic. Specifically, I want them to change based on which option a user selects from another field.

In detail,

Field “Destination” has a list of choices. Then there are two radial buttons in the same group titled “One Way” and “Round Trip”.

Essentially, I need the field “Total Miles” to do one of two things. Preferably, I would like it to calculate the miles based on the two choices. Or, I would like it to pick the value based on those two choices.

EXAMPLE: Destination A is picked with “Round Trip” option. “Total Miles” should be set to 2X the miles value. Miles value would be total miles from host location to the destination (Doesn’t change).

I have seen this post, but it doesn’t quite meet what I’m needing. The values aren’t duplicating, they are being picked based on another criteria.

I also saw this post which should mean that what I’m asking may not be possible. However, I am completely open to doing this strictly in Writer or Calc if need be because I can print it just the same. Having the functionality in the PDF just makes it easier to share and for others to use.

Here is the file in question.
Request For Reimbursement - IT.odt (152.3 KB)

For some reason there is an instruction in German language for using Writer (layout) as a base for Scribus to create a calculation sheet. See here: Rechnen im PDF-Formular (LibreOffice - Scribus). For implementation of JavaScript you have to use Scribus or another PDF editor. LO cannot do that.

Cheers

Thank you all for your time!

The good news is that I was able to turn a paper form into a much prettier and easier to fill out electronic form for free!

I believe I will look into Scribus for fun, but for now I’ll just enjoy the fact that I can do the math myself, but don’t have to write it out!

But as Mike said in the other thread: This needs scripting inside the pdf. If you write the scripts, you could use Scribus to insert them, but not LibreOffice.
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PS: Scripts in pdf are not allowed everywhere. Often they are disabled for security reasons…

Thank you!