The airline, the biggest carrier at Gatwick airport, said its pre-tax loss narrowed by a third to £78.7m on revenues 13 per cent higher at £1.17m for the six months to the end of March.
In January, EasyJet said it expected to post a first-half pretax loss of between £80m and £95m
The company said in a statement: "Estimated full year pretax profit would have been in the range of £175-£200m at current exchange rates and fuel prices, prior to the recent volcanic ash related disruption.
"This disruption has caused additional cost and lost contribution estimated at between £50m-£75m.
"Therefore, the company has revised its profit expectations for the year to a range of £100m-£150m at current exchange rates and fuel prices."
EasyJet shares have risen a fifth this year, valuing the business at around £1.9bn.