What changes can I make to the sheets without worrying about breaking Tiller function?

I’m a newly arrived Mint survivor. I’ve got Tiller installed and banged into a good shape for 2024. I think. It all looks good to me so far.

I have enough technical skills to tailor the sheets and write some script code when needed, to get some functionality that is specific to my needs. But I don’t feel perfectly safe in knowing what I can and can’t do that doesn’t risk breaking something in Tiller processing. I know of course that deleting columns in any of the Foundation sheets would likely cause problems. But do I have complete freedom to:

  • add new columns
  • reorder columns
  • replace constant values with calculations
  • add my own script code

That’s the general question, and if there’s documentation somewhere that would have answered this without me posting a question, I apologize but please tell me where to find it.

An example of where I need to know this is an idea I have for doing a simple version of rollover budget. The idea is to add an Annual Budget column to the Categories sheet, then use this column in conjunction with YTD expenditures in each category to automatically distribute the remaining budget over the remaining months. Essentially,
(AnnualBudget - YTD expenditures) / # of remaining months = future monthly budget

Having some fun getting to know Tiller and it’s starting to work for me rather than the other way around.

Thanks - Bill B

For many edits it does depend on which sheet you’re making changes to and if those changes are on a data reference. A good rule of thumb is to not change any sheet names, headers, or add formulas to those areas.

If you’re using Google Sheets you can always just make your edits and if something breaks, use version history to undo your changes.

What constant values are you trying to replace with calculations?

Also, I’m not sure about the scripts. Maybe @randy would have a better idea there.

We do have some documentation for specific sheets:

Editing the Transactions sheet

Customizing Categories

Thanks for the reply Morgan.

The example I gave was replacing the monthly budget numbers in the Categories sheet with a calculation like I suggested, providing a kinda-sorta rollover budget feature. I have not implemented this yet (or really even thought very long about it), but I think it would provide rollover budget numbers in a simple way.

I just did this myself and was able to locate all the places this had implications. My formula for the monthly budget in the categories sheet now looks like:

=$E2+ifna(VLOOKUP($A2, Recur!$G$1:$S$99, 1+MONTH(F$1), FALSE), 0)+SUMIFS(Rollovers!$C$2:$C$1000, Rollovers!$A$2:$A$1000, $A2, Rollovers!$B$2:$B$1000, F$1)

In column E I added a fixed value, then basically this looks up two different calculations that I make in sheets that I created for recurring transactions and budget rollovers.

Just a note to state the obvious…

When I first started, I made a copy of my Tiller sheet before every anything. I discovered that rolling back to previous versions sometimes failed but having a copy on hand was like gold. I must have broken it and and was rescued by my backup more than a dozen times… actually many more than a dozen times. It’s one of the great things about Tiller.


Excel has a version history if you need to restore a previous version. Restore Excel file


Great tip, @d44clark.