Hundreds of thousands of tenants were hit tonight with rent hikes that are the highest in five years — 4 percent for one-year lease renewals and 7.75 percent for two years.

The increases, voted at a noisy hearing of the Rent Guidelines Board at Cooper Union, affect residents of the city’s one million rent-stabilized apartments whose leases expire on or after Oct.1.

The last time the board slapped tenants nearly that hard was in 2008, when it meted out increases of 4.5 and 8.5 percent.

Last year, tenants got off relatively easy with boosts of just 2 and 4 percent.