A report by the Institute for Fiscal Studies says that pupils who have lost six months of normal schooling could lose approximately £40,000 each in income over their lifetime.
For 8.7 million school children in the UK, this makes a total of around £350bn and a "massive injection" of resources is needed to help them catch up, the IFS said.
The paper suggested learning time could be maximised by allowing students to repeat a school year, lengthening the school day, or extending the academic year.
The IFS paper warned: "Without significant remedial action, lost learning will translate into reduced productivity, lower incomes, lower tax revenues, higher inequality and potentially expensive social ills.
"The lack of urgency or national debate on how to address this problem is deeply worrying.
"The necessary responses are likely to be complex, hard and expensive. But the risks of spending 'too much' time or resources on this issue are far smaller than the risks of spending too little and letting lower skills and wider inequalities take root for generations to come."