Excel, but it's painful - as any change's through the year make it very hard to compare and contrast actual to budget (e.g. a simple rate change from a supplier vs adding someone to a team, moving different rate people between teams) and quite challenging to do different scenarios (e.g. impact of different inflation levels for different roles / countries). It is possible but requires a lot of discipline and excel expertise from everyone to make it work. I am exploring using a planning & budgeting tool (anaplan, pbcs).