When the Museum of Modern Art announced in 2004 that admission to its new facility would cost an eye-popping, and wallet-lightening, $20, a symbolic threshold was crossed, and it was only a matter of time before someone else caught up.Yesterday, the Metropolitan Museum of Art announced that, as of August 1, its recommended adult admission would go up to $20 from $15, bringing it onto a par with MoMA.

The Met’s spokesman, Harold Holzer, said that ongoing deficits necessitated the increase.”Ever since 9/11, the museum has faced the ongoing challenge of a structural,operating deficit,” Mr. Holzer said. The deficit for the fiscal year ending June 30 was $3.5 million. “This is a solution that helps us defray the cost of running essentially the largest museum of the country, while still protecting the concept of pay-as-you-wish.”

The price increase will not affect students or seniors, for whom the suggested donation remains $10. Children under 12 and members get in free.

Unlike MoMA, or the Frick, or the Guggenheim, or other uptown museums, the Met’s admission fee is only a suggested donation, although Mr. Holzer said, “We’re not shy about asserting that we ask visitors to pay whatever they can.” He declined to say how many people pay the suggested rate.

The suggested-donation policy is a requirement of being part of what is called the Cultural Institutions Group, a group of 34 New York City-owned institutions that also includes the American Museum of Natural History, the Brooklyn Academy of Music, the Brooklyn Museum, and the Bronx Zoo. As part of the same deal, the city provides 11% of the Met’s total budget, according the Department of Cultural Affairs. In the last fiscal year, this came to about $24,598,000, an amount that contributed to general operating costs, as well as paying for heat, light, and power.

Many museums around town have been raising their prices recently. In the spring, the Whitney Museum of American Art increased its admission fee to $15 from $12. “We felt that, compared to other museums of our size, we were really underpriced,” a Whitney spokeswoman, Jan Rothschild, said. “The Guggenheim is $18, MoMA is $20. Most of the other museums of our size were charging at least $15, so we felt that this was appropriate. We hadn’t raised our admission in six or seven years. It was just time to.”

Other museums where admission costs more than a movie include the Frick Museum ($15), the Neue Galerie ($15), the Morgan Library ($12), and the Cooper Hewitt (also $12). The Brooklyn Museum of Art, which prides itself on the diverse audience it attracts, reluctantly raised its admission recently to $8 from $6.

Because it belongs to CIG, the Met had to consult closely with the Department of Cultural Affairs about the price increase. A spokeswoman for the department said that because the increase is part of a suggested admission, it will not impact public access.

A painter and the coordinator of the painting department at the New York Academy of Art, Wade Schuman, said he didn’t mind the fee increase and didn’t think it would discourage artists or young people from going to the museum. “Most artists do not give the suggested donation,” he said. “I’d be curious how many people actually do. I think that changing the suggested donation is mainly going to affect out-of-towners and Europeans.”

To Mr. Schuman, the suggested-donation policy still sets the Met apart. “The Met is the last good deal in New York,” he said. “Considering that there’s been huge museum inflation all over the world — which, to me, goes against the whole notion of a museum being for the people — that they only have donations is really symbolic. It’s like Central Park and the Met are for everybody. It’s one of the things that makes New York really great.”