Time's almost up for the UK's biggest companies to publish their gender pay gap, but so far only a third have done so.
Two weeks before the deadline, more than 6,000 companies have not disclosed the average difference between what they pay male and female employees.
Noncompliant companies face legal action, the government has warned.
The CBI says it's difficult for some firms to compile the data, and that smaller companies need more support.
Want to find out the gender pay gap at your company? Try the calculator below.
If you can't see the calculator, click here.
What happens to companies that don't publish?
The Equality and Human Rights Commission (EHRC) says it will be "fully enforcing" the pay gap legislation and will write to companies that do not report by the deadline.
Firms could face an unlimited fine if they continue to fail to publish the figures.
Equality campaign group the Fawcett Society said it should be easier for the EHRC to use its powers.
"Government must make the Equalities and Human Rights Commission's enforcement powers stronger by changing the law," Fawcett Society chief executive Sam Smethers said.
The Commission should have civil enforcement powers similar to HMRC, which has the ability to fine firms for minimum wage transgressions more quickly, she added.
What have we learnt so far?
Most firms pay men more than women. More than three quarters of organisations that have published have a gender pay gap. About 14% pay women more on average than men, while 8% said they have no pay gap at all.
Some of the biggest pay gaps are in aviation and financial services. Jet2.com, Thomson Airways, TUI airways and Easyjet all have median pay gaps between 45% and 50%, which many of them attribute to the prevalence of male pilots. The finance and insurance sector has the biggest average gap of 35.6%, according to the ONS.
No 'quick fix'?
Brenda Trenowden is global chair of the 30% Club, which aims to increase the number of women on boards. She said revealing pay gap figures is not a "quick fix" to solving complex issues of equality and representation in the workplace.
"Rather than just talking about the shocking extent of the gender pay gap, we need to focus on what companies need to do to overcome the structural imbalance behind it," she said.
"There are a combination of factors - including better management of women, appropriate senior role models, and breaking down the gender bias - which need to be implemented as basic steps towards achieving this.
"There is far too much sensationalism and blame around this topic. We need constructive comment around why the gap exists and what can be done to overcome it."
Neil Carberry, of business lobby group the CBI, said these figures are of not much use in a vacuum.
The business industry group is encouraging its members to publish an action plan alongside their figures in order to "make sure the transparency means something," he said.
He added that the UK will see a "significant surge" in reporting over the next two weeks but added "it's a complex task, especially for those [firms] just over the threshold".
"I expect non-reporting will cluster around the smaller end of the reporting group and a good policy would be to help these companies, rather than smack them over the head with a big stick," Mr Carberry said.
Want to learn more about the gender gap? Try asking our bot below.
What's the difference between equal pay and gender pay?
Equal pay and the gender pay gap are two different things. Equal pay is awarding men and women the same amount to do identical or equivalent work. This is a legal requirement in the UK and has been for many years.
The gender pay gap is the difference between average earnings for men and women. If women are being paid more, that's called a negative pay gap.
Under new legislation, companies with 250 employees or more are legally required to publish their gender pay gap by 4 April, while the deadline for the public sector is 30 March.
Having a gender pay gap isn't illegal, but failing to publicly disclose a figure by the deadline is. Companies are also encouraged to publish an action plan if needs be, to show how they intend to address the gap.
The UK has a national median pay gap of 18.4%, as of April last year, according to the Office for National Statistics (ONS).
This is calculated by using the median average for men and women, which is the level of pay that half of people earn more than, and half earn less than.
It's calculated on an hourly basis and includes full time and part-time workers. It's the key measurement used by the ONS.
Companies have to publish both the median pay gap for their employees and the mean average gap, which is all salaries added together and divided by the number of people on the payroll.
Data as of 8am on 20 March. Individual company data has been reported by companies to the Government Equalities Office. All gender pay gap figures in this article reflect the hourly median pay gap for all employees. The national and sector gender pay gap figures come from the 2017 ONS ASHE survey.
Design and development: Evisa Terziu and Sumi Senthinathan
Data journalism: Will Dahlgreen, Ransome Mpini, Daniele Palumbo and Clara Guibourg