Women typically ask for a fifth less salary than men when applying for the same job, according to data released by Reed.co.uk.
It found for jobs where women said their anticipated salary was £19,900, men asked for £32,800 instead.
Jobs with the largest differences were those in accountancy, where women with the same level of experience asked for £36,400, while men asked for £47,000 – a gap of 29%.
Women in East Anglia have the lowest expectations compared to their male counterparts - men expect to earn 19% more than women in the region. This is followed by East Midlands (18%) and the South West (17%).
According to The World Economic Forum the UK already lags behind Nicaragua, Bulgaria and Burundi in equal pay. For every £1 men earn, women in the same job still earn around 80p.
Earlier this year the UK fell out of the top 20 most gender-equal countries, hitting a low of 26 in the 2014 Global Gender Gap Report.
Average wages for women fell by £2,700 in a year to £15,400, according to the Forum, while the average salary for men was unchanged at £24,800.
If you want to know more about how to build a pay and reward strategy that works for everyone, visit the Reward Live conference on 13 and 14 May at Edgbaston cricket ground, where creating a successful approach to pay is just one of the topics on the programme.
Find out the latest thinking on workplace pensions and the new retirement rules, wellbeing for employees, mental health at work, childcare and flexible working, building great leadership strategies and making benefits work for all of your employees.
It’s free to attend for HR and reward directors, business leaders, talent managers, payroll staff, finance directors and anyone else involved in rewarding staff at work (places subject to approval). Visit www.rewardlive.co.uk for more details.