Fat FIRE is the opposite of the minimalist route — you want to retire early AND keep a comfortable lifestyle (holidays, a decent house, no spreadsheet at the restaurant). That means a much bigger number, and timing matters more than people realise because you're funding a long, high-spend retirement. This calculator shows whether your plan actually supports the lifestyle you have in mind, across the full stretch.
Put in your age, savings and target, set your spending honestly (this is the one people lowball), and see what a comfortable drawdown looks like over 35+ years. Just try it — no signup, no bank login. Then run the survival test, because a fat budget is exactly the kind a bad early market can erode.