calculating break-even point for budgets

Hello Rik1234 and Welcome to Excel Forum.
Please utilize the instructions in the banner at the top of the page to upload a sample of your budget. Please manually include the liquidity based on the sample and, unless it is blatantly obvious, the method by which you manually made the calculation so that we will have something with which to compare the output of any proposed formulas/code.
Based on you description of the spreadsheet, would you be open to suggestions on changing the layout? It is often easier to make a calculation when using row over row data entry rather than matrix style e.g. 24 columns of months.
Let us know if you have any questions.

What you do now manually sounds like something that Goal Seek or Solver could replicate.
https://www.excel-easy.com/examples/goal-seek.html
https://www.excel-easy.com/data-analysis/solver.html

You have not described your budget in any detail, but, my best guess is that this factor could be solved for algebraically -- if you were allowed to step away from Excel and look at the problem algebraically. If this is something that you need to do frequently, then I would step away from the spreadsheet and look at the problem that way.

That means exploring the algebra behind the problem to see if I can "solve" for this factor directly. I often see problems on the forum that reduce to something like y=x+0.1*x +k, and the user wants to solve for x using Goal Seek. Of course, in a simple case like this, it is relatively easy to solve for x directly and avoid Goal Seek. My suggestion to step away from Excel is just that, step away from Excel, write out the problem algebraically, and see if it is possible to solve for your "factor" without using Goal Seek. What you describe looks something like y=sum(factor*revenues)-sum(costs). If it is that simple, factor could be easily solved for directly.