That equates to $2.08 to $2.30 per share after taxes, the Worcester-based insurance holding company said.
The quarterly loss estimates are primarily due to a series of tornadoes that affected Joplin, Mo., and surrounding states at the end of May.
In Joplin, the death toll surpassed 150 and an estimated 1,100 people were treated for injuries.
To a lesser extent some damage was due to tornadoes and wind on May 31 and June 1 in Massachusetts, the company said.
The property and casualty insurance provider previously announced estimated catastrophe losses for the month of April to be between $70 million and $85 million before tax.
Hanover is the holding company for a group of insurers that includes The Hanover Insurance Co., Citizens Insurance Co. of America, and Chaucer Holdings PLC, based in London.