A comprehensive study released today by Washington Consumers' Checkbook of the terms offered on checking and savings accounts at 133 area banks, savings and loans and credit unions shows individuals how to match them to their own income levels and financial habits, thereby maximizing their interest earnings.

According to the authors, selecting the right financial institution for one's checking account can make a difference of $160 a year to the customer. They also screened terms offered on savings certificates and repurchase agreements and found a $400-a-year variation in interest on a $10,000 investment.

The highest earnings on interest-bearing checking (NOW) accounts for all customers were registered at savings and loans and credit unions, rather than commercial banks. Checkbook rated the 10 best savings and loans as follows: John Hanson, Chevy Chase, Friendship, Montgomery Federal, Mount Vernon, Suburban, Guardian Federal, Metropolitan Federal, Continental Federal and Northern Virginia Federal.

Top among these are state-chartered S&Ls, which can pay higher interest rates. With the exception of Guardian, which has one office in the District, the others are in the suburbs.

Credit unions offering deals as good as or better than those at S&Ls are: Naval Research, Fairfax School Employees, Potomac Community, Washington Telephone, and Navy Federal.

Checkbook gave its lowest ratings to these institutions: United National Bank of Washington, Maryland National Bank, McLachlen National Bank, Hospitality Community Federal Credit Union, Jefferson Bank & Trust, Equitable Trust, United Savings and Loan, American Indian National Bank, Women's National Bank, Industrial Bank of Washington. The majority are located in the District.

The publication includes a worksheet that enables individuals to calculate the earnings on their accounts and shows how to improve those earnings by shifting balances among different types of accounts: regular checking, NOW, savings, and money market mutual funds. Because these calculations are somewhat complicated, Checkbook has worked up five profiles of hypothetical accounts so customers can choose those most similar to their own.

For example, Profile A is for a person with relatively high income who deposits a paycheck of about $1,800 twice a month. The balance in the person's checking account varies by about $900 each month. He or she is assumed to have $2,000 in a money market fund earning 15 percent.

The highest annual after-tax earnings for Profile A from a combination of a money market fund and a checking account at a District bank at the time the survey was taken last November was $245 at both American Security and NS&T. The lowest, $166, was at United National. The top combination in Maryland, $247, was at United Bank & Trust; none paid under $200. Virginia banks did slightly better: The winner was Dominion National at $255.

All of these figures represent the optimum return, made possible by a judicious shifting of funds. Checkbook offers this advice: "In general you will find that it makes sense to move money out of a money market fund into a transaction account if the transaction account's service fees are high, its balance requirements are low, and money market yields are low." To illustrate the point, Profile A is also calculated with a 10 percent yield on the money market fund. (The difference in various money market fund yields is not taken into account in the examples given.)

"But if the transaction account's fees are low, its balance requirements are high, and money market yields are high, you'll probably find it pays to move money out of your transaction account and into your money market fund; you can pay the fees for a few months with your extra money market fund earnings."

The best combined deal among savings and loans in the District was at Guardian, $266; in Maryland, at Montgomery Federal, $277; and in Virginia, at First Federal of Alexandria, $273. Among credit unions, the winners at $289 were Fairfax School and Naval Research Lab.

Profile C presents the other extreme from Profile A. A $200 difference between high and low balance suggests the account holder deposits a $400 check every other week. The person does not have a money market fund and so the choice is between keeping funds in a checking or savings account.

The most interest this account could earn at District banks was $13 at Security National and Madison National. By contrast, the account would have incurred an annual charge of $54 at United National. Five Maryland banks paid the same $13 interest as did four Virginia banks. The top bank deal of $17 was at McLean Bank.

Among S&Ls the highest earnings in the District were $28 at Guardian Federal; in Maryland, $38 at Chevy Chase and Friendship; in Virginia, Continental Federal, Mount Vernon and Suburban all paid $28. The maximum at credit unions was $36 at both Naval Research Lab and Potomac Community.

The survey also compares rates on savings certificates and money market funds, check holds and fees for bounced checks.

For further information or to obtain the publication, contact Washington Consumers' Checkbook, 1518 K St., NW, Suite 406, Washington, D.C. 20005; 347-9612.