July 31 (Reuters) - International Paper IP.N missed Wall Street estimates for second-quarter profit on Thursday, hurt by steeper input costs for its corrugated cardboard and fiber packaging products, sending its shares down 7% in premarket trading.

The Tennessee-headquartered firm, which reported its first full quarter since buying UK rival DS Smith SMDS.L, said its margins were affected due to higher costs and muted demand in Europe.

International Paper, the largest packaging company in the world in terms of revenue, has closed underperforming facilities both in the U.S. and Europe as well as exited some businesses, such as its molded fiber unit, to increase productivity.

It has also raised product prices to offset the impact of steep input costs.

The company reported adjusted profit of 20 cents per share for the three months ended June 30, well below analysts' average estimate of 41 cents per share, according to data compiled by LSEG.

British packaging firm Mondi's MNDI.L profit also fell for the first half of the year due to higher costs, even as the company warned that a challenging economic environment would persist for the rest of the year.

However, International Paper expects stronger global revenue and earnings in the ongoing quarter.

The company's second-quarter net sales rose nearly 43% to $6.77 billion from a year ago, edging past estimates of $6.71 billion.

(Reporting by Juveria Tabassum in Bengaluru; Editing by Shreya Biswas)

((Juveria.Tabassum@thomsonreuters.com;))