Splitting chores - what's my fair share?

It has to be averaged over a week as not all chores are daily.
Some are not even weekly - who will wash the windows once in a while?

Money doesn't come into it.

The ultimate goal is that you both have the same number of 'free' hours, whether you use them for going to the gym, meeting friends, or just sitting on the sofa watching TV.
Rather than starting from dividing up chores, start by counting your and his free hours.

He's a lazy pig who wants a servant.

I'm another one who doesn't see why the incomes were relevant to the situation but hey ho.
What does he do on his four days off OP?

It should be 50/50 but it wouldn’t be 50/50 each day but averaged over the week. On the days that he works and is out of the house for 12 hours, I would expect you to be doing the housework. He could then do the housework on the 3 days he isn’t working and you are. You would then with we have a day where you both share it or realistically do nothing because you’re two adults working part time and can’t really generate that much housework. I guess it would just be cooling and you could eat out or just alternate weeks.

Do not have children with a man who doesn't think it fair he shares the load.
It is foolish and leads to huge regret.
Simply not worth it.
You are not his housekeeper.
Stop doing anything for him like laundry immediately.
His attitude is not good at all.
Take it seriously.

I would say on his 3 working days you do everything. On the 3 other days you are working and he is off he does 75% you do 25% . And on the day you are both off split 50:50.

Unless there js a drip feed about health issues or something, if he's this lazy and entitled whilst having 4 days off a week and a partner who also works very part time, I would seriously question whether he is someone I'd want to spend the rest of my life with and definitely whether I would want children with you.
You currently both must have oodles of free time and there's only so much mess two adults can make. I can't see how the issue of what is a fair split of doing chores is coming up when there can't be that many to do and you both have plenty of time in which to do them.
I realise he might not want to do much on the days he is out for 12 hours but he can easily then catch up on his days off or take on the chores on those days.

Your income is irrelevant.

Your DP is at home 4 days and you work six half days which is the equivalent of 4 days so it should be a 50/50 split.

Your DP should do his share of the chores over his four days off and on the three days when he is out all day and has a long commute it would be nice for you to make the dinner and do any tasks which absolutely need to be done on those three days as you have the time.

He does bins and washing clothes
I do dishwasher, vacuuming, clean bathroom, kitchen sides, dusting etc

He works full time, I work 2 days and look after our 2yo

If the situation has evolved you need to actively un do it.
DH I am not prepared to be the only one that cooks - 3 days a week when you aren't working meals are your responsibility. 4th day is for take aways etc.
Unless you want to do an ill cook you wash situation - but if you have a dishwashers it's unequal... unless your meals are chucking things in the oven.

I think on the days he's doing 12 hours you should be doing most of the chores but on the 4' days he's off he should be doing most of the chores.
Is there really much to do though. Cooking and washing up obviously but do you have much laundry? Do you create a lot of mess? What it was just me and DH it took us about an hour maybe a bit more to get the cleaning done twice a week and only did washing twice a week.
So working on that it should be easy enough for you and partner to spend an hour a couple of times a week to clean. Then split the cooking and washing up so you do it on his long days but he does it the rest of the week.
Time for a talk with him about splitting chores, although I'd be interested to know what you say when he says you're at home all day, do you point out that so is he 4 days a week

What did you discuss before you decided to move in together?

With only two adults both working in part time, I would expect to hardly notice doing chores. Did he expect to do none once you moved in together?

For comparison

I work about the same hours as DH, but my commute is 75min/50miles each way,. I leave home 6.45am and get back 6.30-7pm. DH works from home 3 days a week and 20min commute the others.

We have 4 children and 2 dogs - busy home

DH does all the cooking, laundry, dishwaher, etc in the week. I am simply not home to do it and its done by the time im home. He is also default parent for issues with the children in the week, due to closer proximity.

But then at the weekend, I do all our deep cleaning - hoover, mop, clean oven, put accumulated stuff away, put away laundry, and so on.

We share the rest on the basis that noone should be sitting around doing bugger all while the other is busy and would benefit from help

You need to do slightly more as he works/travels 36 and you 20. So approximately 60/40.
Sounds like you will be lucky to get him to do anything. Good luck.

I wouldn't expect him to do anything on the 3 days he's out at work as it seems he's out of the house for 12 hours, so think it'd reasonable you'd sort evening meal on those days and whip round with the Hoover if needed.

However the other 4 days he's home he should be contributing fully.

Why does he think that he should just get 4 days fully off (no work and no household responsibilities)? What is his thinning behind him not even doing 50/50 for those 4 days?!

Chores 50/50 but your working hours are bemusing. Your household income is low. Is it a deliberate decision to both be part time and on very dissimilar hours? You in particular seem to get a rubbish deal having to work 3 or 4 hrs on multiple days. I can see why he says you're at home anyway as you are basically tied to home every day! Could you work a few more hours and outsource cleaning jobs?

50/50 is fine, you're both part time so should have loads of time to get housework done.

He sounds quite entitled so would probably avoid kids with him unless he grows up ALOT

Of course he thinks it's okay. He is doing nothing while your doing everything. He's a lazy man child. The jobs should be split 50:50. He has 5 days that he can do his share.

I don't see what imcome has to do with it?

Why do you both work such short weeks, just out of interest? You don't mention children.

You earn more than him in shorter hours and do all of the housework and cooking etc; what exactly is he bringing to the table?

Do you have kids?

Why does he think that cleaning up after him is your job? Is he misogynistic in other ways?

Ha. I'm sure he does. Let him know you disagree, you are not his mother and having to take care of a fully functioning adult can only build resentment and take away any respect or desire for him. Ask him if that's what he wants.

And if you are planning on having kids with their guy, do not until it is super clear what that will look like for you both.