WASHINGTON — Starting now, the price of a stamp won't go up faster than the rate of inflation, the Postal Service said Thursday.

Under a law passed last year, the post office would have been allowed one more rate increase under old rules that could have permitted a larger increase, but which would have involved longer, more complex procedures than the new system.

The postal board of governors decided to forgo that last increase and said that when it seeks rate changes it will follow the new procedures adopted Oct. 29 by the independent Postal Regulatory Commission. Under the new rules the post office will have to keep its rate increases at or under the rate of inflation for first-class and standard mail and periodicals, but will have greater flexibility in setting rates for parcels and Priority and Express mail.

The agency also announced it finished the fiscal year Sept. 30 with a smaller loss than expected.

While the post office ended the year $5.1 billion in the red, that was about $300 million less than projected.

The loss was a result of a required contribution to set up an employee retirement health benefits fund. Without that requirement the agency would have ended the year with a $1.6 billion surplus.