The American Ballet Threatre has canceled its customary three-week spring engagement at the Kennedy Center next year due to the increasing costs of hotel rooms and projected cuts in government grants.

The company, which is the Kennedy Center's "official" ballet company and is directed by Mikhail Baryshnikov, will have its usual four-week run at the Kennedy Center next fall, said executive director Herman Krawitz. He noted that the price of hotel rooms in Washington increased during the spring tourist season, and these costs, added to recent salary increases, would make the normal financial loss on tour "excessive."

"You have cherry blossoms, the bills go up," Krawitz said. "That's not my fault."

The ABT's visits to Washington involve about 125 people at a per-person daily hotel cost of between $20 and $50. The dancers usually stay at the Guest Quarters, with the principals at the Watergate or Howard Johnson's. Krawitz said that predicted cuts in the National Endowment for the Humanities dance touring grants will create a deficit that the Kennedy Center would not be able to make up, a fact confirmed by Thomas R. Kendrick, the Center's director of operations.

The hardness of the dance floor in the Opera House, which caused the New York City Ballet to cancel its engagement next October, was not a factor in the ABT's decision, Krawitz said. "They've worked very hard on it," he said.

The Center is waiting for the verdict on a new floor the New York City Ballet will test in October in Fort Worth, Tex., Kendrick said. If the floor is a success and the Center buys it, it is likely the New York City Ballet will return in 1982.

The last time the ABT canceled a run at the Kennedy Center was in December 1979, due to a lockout over a disputed contract renewal that lasted two months. Under the terms of the settlement, the ABT management agreed to pay for the dancers' hotel rooms while the company is on tour and to allot $20 per day for food.

"This [the cancellation] should not be interpreted as a reduction in the amount of dance at the Kennedy Center," Kendrick said. "Next season will have the same level of dance as last season, and that was the most we've ever had." He listed eight small contemporary companies, including those of Jose Limon and Twyla Tharp, and four large companies, including the Royal Danish Ballet, the Maxzowsze company from Poland, the Joffrey Ballet and the Dance Theatre of Harlem.

"Washington still gets more of ABT than any town other than New York," Krawitz said.