But not only are these folks paying fund fees on the investments in their plans, about 95 percent are also paying administrative and other fees, since many employers pass some, or all, of those costs on to plan participants.

To help participants become more savvy about the fees they pay, TD Ameritrade has teamed up with fintech firm FeeX, Inc. to help retirement savers quickly analyze their 401(k) fees.

The result, a free 401(k) fee analyzer tool powered by FeeX, allows them to find out what they’re paying in fees for their 401(k), 403(b) or other defined contribution plans.

The tool analyzes overarching administration fees, as well as individual fees for the mutual funds within the plan, so that individuals see a detailed view of their specific investment holdings and plan services fees.

Users can then use that to conduct an objective, side-by-side comparison of the fees associated with their 401(k) account(s) versus other potential fees in an IRA.

The survey also finds that nearly three-quarters of 401(k) owners left an account behind at an old job, with 31 percent ending up rolling it over into a new employer’s plan and 34 percent putting those funds into an IRA.

Many who roll funds over into a new boss’s plan do so because they think it’s cheaper—those fees again—but that’s not necessarily true. Institutional pricing on funds can make IRAs cheaper; it depends on what’s in both plans.

Of course, 22 percent of those who take a new job end up leaving their 401(k) funds with their former employer, but that doesn’t necessarily mean they’ve checked out the alternatives to see whether an IRA might serve them better on fees.

And 13 percent of workers just cash out their plan when they leave the job, and that could cost them a lot more in taxes and penalties—not to mention lost opportunities for retirement earnings. They, too, might make other choices if they had the chance to compare account costs.