The Washington Post increased the subscription price for daily and Sunday home delivery of the newspaper yesterday by about 11 percent.

Effective Monday, the home delivery charge went to $6.20 every four weeks from $5.60. The previous rate and four-week billing cycle had taken effect on Feb. 1, 1977.

The newsstand price remains the same.

Noting that President Carter's guidelines call on companies to slow the rate of price increases, Post Publisher Donald Graham said that because other circulation rates will not be increased, the overall increase in circulation revenues would be about 7 percent.

The only other Washington Post circulation price change since the daily and Sunday delivery rate was raised more than two years ago was a boost in the Sunday-only home delivery and newsstand rate in March 1978 to 75 cents from 60 cents.

According to Martin Cohen, vice president and treasurer of the Washington Post Co., which owns the newspaper and other communications properties, the subscription rate boost will bring in about $3.4 million a year in additional revenues -- less than one percent of company-wide revenues that exceed $500 million.

For the balance of 1979, the rate hike yesterday will bring in about $1.5 million to The Post newspaper and an additional $700,000 for carriers, Graham said. Government price guidelines cover entire company operations and not just one product, and Post Co. officials said the firm is in compliance with the Carter standards.

"Since we last increased home delivery prices, newsprint prices have increased 13 percent," Graham stated. "In fact, the newsprint alone in a daily Post now costs an average of 18 1/2 cents."

He added: "We've tried to keep The Post a paper everyone can read and a paper everyone can afford; at a time when a phone call or a postage stamp costs as much as The Post, I think we've succeeded."