That is more than double its original estimate made in July, when it warned of a £40m hit, reports The BBC.
Jet fuel is priced in dollars, so the falling pound has made it more expensive for Easyjet to run its aircraft.
Easyjet expects a profit of between $490m and £495m for its financial year, which ends on 30 September.
That would be down 28 per cent on the £686m annual profit it made in 2015.
“The current environment is tough for all airlines, but history shows that at times like this, the strongest airlines become stronger,” said Carolyn McCall, Easyjet chief executive.
Easyjet flew a record 22 million passengers in the three months to 30 September, and those passengers have been enjoying lower ticket prices.
Easyjet expects revenue per seat to be down 8.7 per cent for the year and expects ticket prices to fall further in the coming months.
“Average fares are coming down, which is good for customers. To a certain extent, there is a price war going on,” said Robin Byde, airline analyst at Cantor.
“Passenger growth is very strong, cabins are very full. To do that, they’ve had to discount quite aggressively,” he added.
Terror attacks in Europe, Turkey and Tunisia have also affected sales.
“We have been disproportionately affected by extraordinary events,” said Ms McCall.
