Himalaya I wish it were as simple a calculation as that. The shear biological fact that woman have babies and require maternity leave can bugger up their career, especially in the masculine world of financial services.
I worked full time when ds1 was a baby, went to 3 days a week when ds2 was a baby. This meant my career totally stagnated and I went no further. With baby no.3 I gave up work as it was too much to do my job and have 3 young children. This was going to be only for a few years whilst the children were young. However, during those years, my dh salary and career took off and his salary doubled.
The whole family reaped the benefits of his larger salary, which he could do because I was at home looking after our 3 children. But before anybody beats the feminism drum, that is just biological decisions that someone needed to do it and I was the one who was taking the maternity leave, which was already affecting my career and the way I was perceived in the workplace.
There is no point me coming back into the work place years later and expecting my dh who pays for everything to suddenly take a back seat whilst I get my career up and running, which will take a few years again. Appart from the fact that we can't afford for him to take a drop in salary.
Whilst my salary was £55k plus all the benefits, I would now come into the work place at an utter max of £30k and more likely £25k because I haven't been working for 5 years. That is on the basis of full time working.
If there are any part time jobs, which are like hens teeth in marketing, whilst the full time equivalent may be £30k, so the part time should equate to £15k. Companies advertise the part time roles as £10k. They are normally always 2/3rds of the salary they would be if it were someone who was full time requesting part time working.
If I was only going to work for 1 year possibly 2 on a lower salary before my children were grown and not needing childcare I may take a view that it was worthwhile taking a hit. However, I have another 5 years at least, most likely 8 years before I no longer need significant amounts childcare.
There are thousands of women out there who want a balance of a job that stretches them mentally and uses all their qualifications and experience, but also being there for their children for some of the time (more than the weekend). However, because they don't exist they end up in shitty min wage jobs that they could have done if they left school at 16.
There really aren't any choices between 1 and 50 for women who's salary needs to cover the childcare costs as they get no Government help.
My dh salary covers all the other costs. It costs us as a family for me to work, therefore, it stands to reason that for me to work, my work must cover those additional costs, otherwise why work?