The New York Philharmonic, battered by a pandemic that will keep its concert hall dark for at least 15 months, announced on Monday that its musicians had agreed to a four-year contract that includes substantial salary cuts.

Under the new contract, the musicians will see 25 percent cuts to their base pay through August 2023. Pay will then gradually increase until the contract ends in September 2024, though at that point the players will still be paid less than they were before the coronavirus pandemic struck. The cuts will amount to more than $20 million in musicians’ wages over the course of the contract, the head of the players’ negotiating committee said in a news release.

The deal makes it clear that performing arts institutions expect their financial pain to last, even if the pandemic subsides over the coming months. The Philharmonic projects that the cancellation of its 2020-21 season will result in $21 million of lost ticket revenue, on top of $10 million lost in the final months of its previous season this spring; but even when live performances resume, the box office is not expected to bounce back quickly.

The new contract is a continuation of the short-term pay reductions that the Philharmonic’s musicians agreed to earlier in the pandemic. Since May, the musicians have been paid about 75 percent of base pay, which amounts to about $2,200 per week. Over the course of the contract, some musicians will also receive gradually increasing percentages of their seniority payments and “overscale,” the amount they receive above base pay.

The pandemic has been testing the relationships between arts institutions and their workers, as executives insist on pay cuts and other concessions to make up for the revenue losses accumulated over months of darkened theaters. At many orchestras, musicians have agreed to short-term pay reductions while they are unable to play live concerts. But only at certain organizations, like the Philharmonic, have union collective bargaining agreements happened to expire during a year when institutions are under such pressure.

“There is going to be a road to recovery and we’re on it,” Deborah Borda, the orchestra’s president and chief executive, said an interview on Monday. “If we can make that journey more quickly we will immediately share that with our musicians.”

Ms. Borda said that management has been negotiating with the musicians since early April. An important step in reaching a deal, she added, was transparency about the Philharmonic’s financial status and plans, which helped make clear the need for cuts that could extend beyond the duration of the pandemic.

“Are we happy about it? Absolutely not,” she said of the cuts. “Did we all decide that it was necessary? Yes.”

The trombonist Colin Williams, the head of the players’ negotiating committee, said in the release, “In recognition of the challenges of this time, we have done our part to help preserve the institution by forgoing more than $20 million of our wages.”

The cuts that the musicians agreed to are similar to those being requested at the Metropolitan Opera, which has asked for 30 percent pay cuts from several of its major unions until box office reaches pre-pandemic revenue levels, at which point the cuts will be reduced to 15 percent. For Philharmonic musicians, the cuts will shrink to 10 percent during the last year of the new contract. The deal also includes bonus payments starting in 2022 if the orchestra’s financial performance exceeds expectations, as well as a provision for up to 10 Sunday performances per season. (The Met introduced regular Sunday matinees last year.)

Tensions have been much higher at the Met — where the company’s management said on Monday that it planned to lock out its stagehands because they had not agreed to the proposed pay cuts — than at the Philharmonic. Roughly 1,000 full-time employees at the opera company, including its world-class orchestra and chorus, have been furloughed without pay since April, and the Met says they will only start receiving paychecks during the pandemic if they agree to long-term cuts.