Male teachers earn an average of about pound;70 per week less than they would for a comparable job in the private sector - but women's pay is higher than they would get elsewhere.
Overall, primary teachers are paid pound;23 a week less than they could earn outside the profession and secondary teachers receive pound;26 less, a study of public sector earnings carried out for the pay review bodies shows.
Calculations made by The TES show this pay gap saves the Government more than pound;500 million each year - equivalent to the cost of building 20 academies or one-fifth of the annual uncollected income tax sum.
Union leaders said the study was a "smoking gun" which proved teachers'
salaries need to increase to attract more men into the profession.
The report comes as the Trades Union Congress revealed that teachers work more unpaid overtime than most other employees.
Teachers and lecturers would work until March 22 for free each year if they did all their unpaid overtime at the start of each year - almost a month longer than the UK average.
If teachers were paid for their extra overtime they would earn an extra Pounds 10,000-a-year, enough for a deposit on a home in many areas.
The TUC's calculations are based on data collected before the latest stage of the workforce agreement came into effect.
Mary Bousted, general secretary of the Association of Teachers and Lecturers, said the deal which guarantees teachers half a day week for planning, preparation and assessment was beginning to cut hours. But she said: "There is still a long way to go to ensure teachers and lecturers don't have to work for more hours than they are paid."
The report for the pay review bodies by the Office of Manpower Economics showed male primary teachers face the biggest shortfall. They receive pound;78 per week less than they could earn outside teaching. Secondary men get pound;65 less.
Fewer than one in six primary teachers is a man, a figure which has fuelled concern about the lack of male role models for children.
But female secondary teachers earn almost pound;17 more than their peers in business. Women in primary schools earn about the same as they could expect from a private-sector job.
John Howson, recruitment analyst, said more women in secondary schools had higher pay because they had access to a larger number of promoted posts attracting management allowances.
An extra pound;78 a week would buy 33 pints of lager or a pair of Premiership football tickets. Over a year, it would add up to pound;4,050 - enough to buy a secondhand BMW 5-series or a 10-year-old Land Rover.
The extra pound;26 per week which the average secondary teacher missed out on would buy five bottles of Jacob's Creek Chardonnay or a pair of West End cinema tickets and some popcorn.
The report presents a mixed picture of how teachers' pay compares to other public-sector professions.
A spokeswoman for the School Teachers' Review Body said the findings had come too late to influence its latest report which recommended a 2.5 per cent annual pay increase for teachers until 2005.
Doctors earn pound;300-a-week more than they could expect to get in comparable private-sector jobs, police earn pound;83 more and members of the armed forces get pound;60 extra.
By contrast, prison officers suffer a similar pay gap as teachers, and nurses and midwives earn pound;49 per week less than comparable private-sector workers.
The gap between teachers' salaries and those of comparable private-sector jobs has risen sharply during the past decade. In 1994 and 1995, teachers would have been no better off opting for a different profession. The gap peaked at Pounds 39 for secondary teachers in 1999 and pound;48 for their primary colleagues in 2000 before falling to current levels.
The level of pay teachers could earn in a comparable private-sector job is not based on individual occupations but instead on a statistical analysis of private-sector wages and skills needed for different jobs.
A Department for Education and Skills spokeswoman said: "The relationship between teachers' pay and that of others in the labour market is a fair one. Teaching remains one of the most respected and rewarding professions.
"There has been a 37 per cent real terms increase in teachers' pay since 1997 and a senior classroom teacher in inner London could, from September, now earn up to pound;40,002."