Surely it's not nearly as simple as
(amount saved)/(take-home pay), since if I make pre-tax contributions to a 401(k) or HSA I pay less in taxes, and money I save in not being taxes is, well, money being saved.
But it's not necessarily
(amount saved)/(gross wages), because after-tax savings such as to a Roth IRA or even just to a savings account are, well, after-tax, whereas gross wages are a before-tax number.
I have a feeling that an understanding of what I am paying/not paying in taxes is important to this question, but I can't come up with a simple
SAVINGS_RATE = X + Y + Z equation that also accounts for taxes.
Note that I define savings as "money not to be actively spent" - so retirement accounts, emergency funds, short-term savings for vacations, etc.