Everything in Firecalc is in today's dollars. Even the out put you receive.
For spending, enter what you intend to spend (including all taxes). Firecalc will take into account any retirement income (SS, pension, etc), and will give you a probability based on that.
You can use the investigate tab to back calculate a spending amount based on a probability you select.
If your not living on the edge, you're taking up too much space.
Never slow down, never grow old!