Sorry, 401(K), 403(b) and IRA contributions are all done AFTER payroll taxes are taken out, so are after tax as far as payroll taxes are concerned. But you are right that they are BEFORE income taxes.
Dear rwrcpa1,
I don't know about individual IRAs, but with my SEP IRA, it was pre-payroll tax money that went into the accounts. I'm in the middle of setting up a 401(K) to replace the old SEP, and I'd have to double check, but I believe that through the "salary reduction," and with the employer contribution, both are pre-payroll tax.
sitetest