British mothers are now effectively working for free compared to fathers, as women with children earn £302 less per week, according to analysis of official Office for National Statistics (ONS) data.
It equates to one-third less per week and nearly 20% less per hour, and the result is that Mums’ Equal Pay Day falls today, a full six weeks ahead of Equal Pay Day for all women.
The figures show how parenthood continues to deepen gendered income inequalities, even when mothers return to work. ONS has confirmed the accuracy of the figures, but experts warn the reality may be even worse as the calculation does not include parents who leave the workforce entirely because of care responsibilities.
Motherhood penalty deepens the pay gap
Joeli Brearley, founder of Growth Spurt — a back-to-work support initiative for parents — said the impact of starting a family on women’s careers was profound and structural. “The reason the gender pay gap worsens so significantly after having children is because starting a family has a disproportionately negative impact on women’s earnings,” she was quoted in the Guardian as saying.
She added that many mothers were forced out of their roles due to high childcare costs, experiences of maternity discrimination and unavailability of meaningful flexible or senior roles. “We know that women are much more likely to have been forced to leave their jobs due to childcare costs, maternity discrimination and a lack of suitable flexible working,” Brearley said.
Growth Spurt’s previous research found that around 74,000 women each year leave their jobs after becoming pregnant or taking maternity leave. “The majority of mothers say they’ve faced some form of discrimination or disadvantage as a result of taking maternity leave, from missed promotions to being sidelined at work,” Brearley added.
Structural barriers and policy shortcomings
Campaigners say the problem is compounded by persistent inflexible job structures. The roles most suited to balancing care — typically part-time or hybrid schedules — are often lower-paid and carry minimal promotion trajectories. Women are more likely to take on these roles, making them disproportionately exposed to the so-called “flexibility penalty”.
Brearley was also critical of the design of the UK’s parental leave system, calling it “outdated” and saying that “mothers are encouraged, and often expected, to take extended time off, while fathers return to work quickly”. “This not only entrenches the idea that caregiving is ‘women’s work’, but also means men’s careers continue to progress while women’s stall.”
That stall compounds over years into significant financial setbacks. According to Penny East, chief executive of the gender equality charity the Fawcett Society, “[i]t’s significant that Mums’ Equal Pay Day falls so much earlier than Equal Pay Day. Motherhood can create a financial cliff edge for many women. The motherhood penalty and the gender pay gap conspire to create a pension pay gap, which pushes many women into pension poverty later in life.”
What HR leaders can do
The findings put the spotlight on actions that employers should take. HR professionals and business leaders are being urged to treat the motherhood pay gap not as an HR afterthought but as a strategic priority.
Flexible roles must be reworked — not as lower-tier, low-value roles, but as accessible, progressive career paths with fair pay and growth opportunities. Employers should actively monitor pay gaps between mothers and other employees and use those insights to adjust compensation and promotion practices promptly.
Training for managers is also essential. HR teams should raise awareness of unconscious bias, ensuring that requests for flexibility or career breaks are not seen as career-ending. Return-to-work programmes such as Growth Spurt’s can be invaluable, providing tailored support and reintegration pathways.
