Ask HN: What tools do you use to build a financial model for your business?

I wanted to get feedback from startup CEOs / CFOs about how they build financial models for their startups - projecting things like revenue, operating expenses, capex, working capital, impacts of financing rounds, etc.

Do you build a financial model in Excel / Sheets that is maintained and updated? Are there software tools that you'd recommend to help build and maintain a model / run scenarios to run a business?