The best way to figure this is to calculate what your taxes would be at your desired withdrawal rate, then include that in your projected budget. Don't forget state taxes. The reason most will say depends is that you still get deductions and exemptions, so you will not pay tax on 100% of your withdrawal. This is one of the really useful benefits of having traditional, Roth, and taxable accounts. You can mix and match the different tax treatments to get both the spending and taxable income that is best for you. For example, I plan to spend 60k, taxable withdrawals of 40k, and nontaxables of 20k. After deductions, my final taxable will be 15k, with Fed tax of 1500. That is practically a nuisance expense, not something that dominates my finances.