If you are under 70 years old and still working, expect an extra notice in the mail this summer.

The Social Security Administration will let you know whether its notorious earnings test shows you received too much or too little in benefits last year.If it's too much, you'll have to return the excess. If it's too little, the shortfall will be made up with a deposit to your bank account.

More than 800,000 Social Security beneficiaries are affected by the earnings limit - mainly retirees who work to supplement their retirement income. The earnings test does not apply to income from investments or other sources.

Beneficiaries ages 62 through 64 lose $1 of Social Security benefits for every $2 they earn over a certain limit, which increases annually (it was $8,460 in 1997).

Retirees ages 65 through 69 lose $1 for every $3 they earn over a higher limit - $13,500 in 1997. For 1998, the limits are $9,120 and $14,500, respectively.

Once you're 70, you can earn as much as you like with no cut in benefits.

In addition to settling up last year's account, all beneficiaries who work will receive a form this summer to confirm their estimate for this year's earnings and to project earnings for 1999.

You can call the agency (800-772-1213) to enter your estimate. If you change your estimate for this year, your benefits will be adjusted for the rest of the year.

Before 1997, beneficiaries had to report earnings to Social Security each spring, so the earnings test could be applied. That filing is no longer necessary because the agency uses tax filings to get the information it needs.

John Ferraro, 66, of Las Vegas earned more than the limit two years in a row. When he started collecting at age 62, Ferraro said he had no idea he would be penalized for earning more than a certain amount.

"I earned something like $14,000 that year and the next, and ended up owing Social Security more than $6,000," he says. "It took me three years to pay off the debt. Now when I take a job, I make sure I earn under the limit. I'm not going to pay them any more money."

The earnings limits are raised each year. By 2002, retirees between 65 and 69 will be able to earn up to $30,000 a year without sacrificing any benefits.