Most people can measure their status at work by four P's: paychecks, promotions, performance reviews, and perks. For women, it is paychecks that often speak the loudest about how employers value them—or undervalue them. Despite gains, many women still earn, on average, just 74 cents for every dollar men earn, reports the U.S. Census Bureau.

Do the math: That's 26 cents per dollar lost. Over a working lifetime, the potential income adds up to staggering losses. As one example, the Institute for Women's Policy Research in Washington calculates that the average 29-year-old working woman with a college degree will lose 990,000 dollars to the pay gap over her career.

To emphasize just how much that income gap between men and women costs women, the Working Women's Department of the AFL-CIO last week launched an unusual Web site—www.aflcio.org/women/equalpay.htm—for equal pay. A visitor to the site simply enters her current salary, age group, and education level. Then the screen shows how much the pay gap could cost her.

For a hypothetical 40-year-old college educated woman earning 40,000 dollars, the figure is 844,107 dollars. In real life, of course, some women's losses will be lower—or even nonexistent.

Wage discrimination has been against the law for 35 years. Yet systematic underpayment on the basis of sex and race still pervades the workplace. Since the Equal Pay Act was signed in 1963, the wage gap has closed at the rate of less than half a penny a year, giving new meaning to the term "snail's pace."

Women secretaries, for example, earn about 100 dollars a week less than male clerks, according to the National Committee on Pay Equity. For women lawyers, median weekly earnings are nearly 300 dollars less than those of male lawyers. Median pay for women professors is 170 dollars less than their male counterparts. The list of disparities goes on.

Two myths persist. The first is that women work for extras—vocations, clothes, second cars. In truth, women work for the same economic reasons men do—to pay the rent, buy food, finance college education, save for retirement, and yes, buy extras too.

The second myth holds that the pay gap is a woman's issue. Not true.