Formula to calculate fair split of university costs

[jamaisjedors]

Hoping someone with a maths brain might be able to help me as despite exh being a maths professor, he is refusing to... 🙄

Ds1 is going into his 2nd yr of university (not uk) and I've worked out a budget for him for next year, it'll be around 850e per month plus tuition fees to split too.

This year be was living at home with me and exh continued paying court ordered maintenance directly to me.

From September I want him to be responsible for this own budget as he will be moving out.

I need to set up an excel table where I could put in the total budget, exh's total income, my total income, and then come up with how much each of us some party to make it fair.

Can anyone advise on what formula I some use? I asked chatgpt but it came up with 3 totally different answers which even I could see were wrong!

Otherwise I'll have to ask ds1 to do it himself (maths student too)!

Thanks! ❤️

There's not enough information here to decide a fair split. Can ex just pay maintenance to ds as a starting point?

Unless there is a court order stating that ex pays maintenance during university if your son resides with you (in the UK) then any finance is based on the resident parent (and partner's income) and not a non resident parent at all even if they a high earner and the resident is not.

I suspect in reality where you mention that ex is still paying court ordered child maintenance he is not legally obliged to pay any more than that. So I would suggest he pays that direct to DS and you pay what you want to and DS gets a summer job and/or part time job to top up any student finance.

Ok thanks. Exh is obliged to pay to 25 or whenever the kids are earning independently.

Court order for this is pending but won't be in place til too late.

I now think maybe 50/50 is simpler as negotiations and discussions with exh inevitably end in nightmares for me and it's not worth the stress of negotiating with him.

Thanks anyway

Is there a massive disparity between your incomes? If not, 50-50. If he earns 3x what you do, then you could suggest he pays more.

If you want to ask for a % of earnings the formula would be the sum of your total combined salary divided by your salary then press the % button
Repeat for your exH salary
then it’s =sum(850*x) with x being whatever % popped out from your initial calculations

My post is based purely on the excel formula for calculating % of £850 based on income %

The formula is:
Your share: =SUM(850*(YourIncome/ TotalIncome))
His share: =SUM(850*(HisIncome/ TotalIncome))

You've probably seen different answers because there's separate ways of working out what's 'fair'

Proportional based on gross salary
Proportional based on net salary
50/50 split
Proportional based on disposable income, but then you get into discussions about the definition of disposable income and whether it's personal or household income (if either of you are cohabiting) etc etc

Assuming that a 50/50 split isn't going to be hugely unfair to one of you due to a large difference in available money, then that seems as good a way as any of doing it, and you seem happy with that. Plus you won't need to constantly review it if one of you gets a pay rise, or circumstances otherwise change. Just agree the amount and you both pay half each.

I would just work out the ratio and split it like that.

If you earn 38,000 and ex earns 52,000, you are in the ratio 38:52, or 19:26.

19+26 = 45

£850/45 = £18.89

£18.89 x 19 = £359
£18.89 x 26 = £491

Super helpful detailed answers and formulas, thank you so much! I'm going to copy them down for the future or in case exh refuses a 50/50 split.

Initially I wasn't happy with that, as he does earn more than me for his basic salary and is also still living in the family home for free while I have to rent somewhere expensive while he drags out the divorce....

but then on the other hand this year I have done quite a lot of overtime and taken on extra work which has bumped up my earnings.

Also the stress of the back and forth with him over the last couple of weeks has been affecting my sleep etc and as you say, I don't want to have to do this every year with him.

Thanks again everyone, so so helpful to talk it through on here and get a variety of informed answers and points of view. ❤️