The figure was a notch higher than a flash estimate released by the state-run statistics agency at the start of this month.
In August, the prices of consumer goods and services in Poland were 5.5 percent higher than in the same month a year earlier, according to the Central Statistical Office.
In July, Poland's consumer price index stood at 5 percent, the state-run statistics agency has said.
The Polish central bank’s Monetary Policy Council last week raised key interest rates for the first time since 2012 in a bid to stem inflation.
(gs)
Source: PAP