Lets simplify the math. Im going to invest 1 dollar and it will 10X by the time i withdraw. Roth- Invest 1, pay .22 in income tax today, .78 in my account, 7.80 when I withdrawl --7.80 Trad- Invest 1, pay 0 tax, 1 in my account, 10 when I withdrawl, pay 2.20 in income tax --7.80 It does not matter when you pay the taxes, if the tax rates are the same. BUT, you pay your marginal tax rate when contributing to a ROTH, and Your average tax rate when you withdraw from the TRAD. Your locking in a 22% Tax rate today to avoid an unknown, but likely lower, tax rate when you are in retirement. Using the previous example, If your average tax rate in retirement was 15% You would have 8.50, opposed to having 7.80 With A ROTH, Assuming everything else is equal.