I'm assuming you're talking about Roth versus non-Roth. Mathematically, you're right, they are equivalent if your tax brackets don't change. It's pretty obvious

I'm assuming you're talking about Roth versus non-Roth. Mathematically, you're right, they are equivalent if your tax brackets don't change. It's pretty obvious once you get the correct formulas. The are reasons to prefer Roth: higher contribution limits -- paying the tax liability up front lets you save more for later. You can also pull out contributions to the IRA tax + penalty free, and pull out earnings for limited purposes (medical, downpayment on a first home). And you're not required to withdraw which can save you down the line.