By Robert Barba

Gap Inc. cut its 2021 forecast to account for lost sales from supply chain disruption and a $450 million in air freight as it aims to meet holiday demand.

The retailer said it expects adjusted earnings per share to range from $1.25 to $1.40. The company had previously set a range of $2.10 to $2.25.

The adjustment includes an estimated $550 million to $650 million of lost sales from supply chain constraints. It also includes expenses related to air freight.

The company said it is also moving more product through East Coast ports to avoid the congestion in the Port of Los Angeles.

"While our mitigation efforts are driving significant transitory costs, we view these as investments in preserving market share and driving overall health and relevance for our brands," Finance Chief Katrina O'Connell said in prepared remarks.

"The company noted that when adjusting for transitory costs and sales lost from the acute disruption, the business momentum is strong," it said in prepared remarks.

The company expects full-year revenue growth to be about 20% compared with its fiscal 2020. It had previously guided for a 30% increase.

It expects its operating margin to be 4.5%, or 5% on an adjusted basis. It had previously guided for 7%, or 7.5% on an adjusted basis. It continues to expect to reach a 10% operating margin by the end of 2023.

Write to Robert Barba at robert.barba@wsj.com