Feature Request: Average Value View for Income Statement (per day/week/month)

[richtefee]

Context

In the Income Statement, Fava lets you change chart types, conversions, and filter by time, account, or tag. What I’m missing is a way to show average values per time unit (day/week/month) for the filtered period.

Example:

For a trip from Oct 10–26, all tagged 2025_Holidays, I’d like to see the average cost per day of that trip.

Idea:

Add an “Average” dropdown (similar to the “Conversion” menu) that converts all displayed numbers into averages based on a chosen unit: Daily, Weekly, Monthly, etc. The already known sum and first and last booking slots can be used to calculate this quantities.

Commitment:

I’m new to contributing to Fava but would like to try. A pointer to where this would fit in the code (maybe around fava.core.tree.SerialisedTreeNode?) would be very helpful.

[yagebu]

Would you want to see the average for all accounts or just as an average over e.g. all Income? If it's the latter, I think this could become part of the charts - e.g. by having a line for the average in the bar chart and possibly showing the value on hover. If it's the former, it doesn't really work as a conversion option - those are designed to work across reports and really just "convert" a value - e.g. it does not really make sense in an account journal to have these averages. But I could imagine it as a separate sort of toggle (specific to the tree reports) to basically divide the values by the number of intervals.

See #1619 where a rejected approach to displaying averages for income and expenses was submitted.

[richtefee]

Hey,

thanks for the helpful questions and for pointing out the related proposal. I was indeed thinking of an average over all accounts, mainly for (filtered) Income or Expenses.

Adding a visual indicator (e.g. a line in the bar chart showing the average) sounds like a very nice idea to me. I agree that for choosing the denominator of the average (per day, week, month, etc.), a dedicated toggle (or dropdown) specific to tree reports would make the most sense.

If this direction sounds reasonable to you, I’d be happy to try working on an implementation (hints welcome ;-).