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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

Birthday bill split

1000 replies

KnickerlessFatWoman · 18/07/2026 12:55

Last weekend was my mother’s birthday, so we - that’s me, my parents, sister and BIL and their 12 year-old son - went for Sunday lunch. Unfortunately the food wasn’t great, and they ended up taking my main off the bill.

My dad is someone who always wants to treat everyone, so my sister and I decided this time it was our turn and we were going to treat him and our mum instead. When the bill came, BIL asked if we could split it over two cards, but they said they could only take one payment. He paid and I said I’d transfer my share. For the sake of keeping the maths simple on this thread, let’s say the bill was £210, or £35 per head.

Both BIL and sister are crap at responding to messages, so it took me until midweek to get the bank details. I sent over £70 to cover me and one of my parents.

I heard nothing in response, but I was chatting to my mum earlier and she said “Oh, by the way, Katie said you got the money wrong - it was £210 and you only sent £70”. I said no, that was right - my meal and one other. She said, “Ohhh… I think she thought you were splitting it”. I laughed and said, “No, we said we’d treat you and Dad. I didn’t say I’d pay for three meals!”

I don’t really know why my sister couldn’t just have messaged me instead of talking to our mother about it, but that’s not really the issue. Surely she and BIL don’t expect me to pay half the bill? By treating our parents, I meant exactly that - not that I’d pay for them both while my sister just paid for her own family (which is what this amounts to). There are three of them and one of me. If I pay half the bill, sister and BIL have only covered themselves and their child - there’s no “treating” anyone at all.

AIBU for thinking £70 was my share and paying just that?

OP posts:
changeme4this · 19/07/2026 02:03

OP you are right but you really need to sort this with your sister. Then sort out why she brought it up with your parents and not you.

i agree shouting your parents doesn’t mean a 50/50 split of the entire bill, however that was the starting point for you BIL. They just haven’t thought about the numbers.

KnickerlessFatWoman · 19/07/2026 02:09

Shudacudawuda · 18/07/2026 17:48

I would have just paid half, I do think it comes across as mean.
It's not that you're wrong OP, your arguments are sound and if you were hard up for cash then pretty reasonable. But you've said it's not a lot of money to you so, I don't really get the penny pinching. Its just a nice thing to do, to go 50/50. I personally wouldn't even be thinking of it on a per person basis, we'd just go halves if it was my family.

But why should I pay more? Why can’t my sister and BIL pay for their own meals?

OP posts:
TappyGilmore · 19/07/2026 02:11

OneSparklyGoat · 19/07/2026 01:49

It wouldn’t cross my mind to clarify this. “I’m paying for my meal, not your family.”

Who expects someone to cover their people on a check?

Um, lots of people expect that? It’s quite common to split a bill 50/50 even though people might have consumed food and drink worth differing amounts, so one party is effectively subsidising another.

KnickerlessFatWoman · 19/07/2026 02:13

Swonderful · 18/07/2026 18:26

Did their 12 year old have a share of the wine too?

You know he didn’t. What are you on about?!

OP posts:
OneSparklyGoat · 19/07/2026 02:14

TappyGilmore · 19/07/2026 02:11

Um, lots of people expect that? It’s quite common to split a bill 50/50 even though people might have consumed food and drink worth differing amounts, so one party is effectively subsidising another.

Not to the tune of entire extra bodies. We always divide by people and then pay shares.

So BIL and Sis would pay 3 shares plus 1/2 of the parents’s bill.

Only a true cheapskate would expect a single person to pay the same as an entire family.

AnnoyedAsAllHeck · 19/07/2026 02:15

KnickerlessFatWoman · 18/07/2026 13:11

As I say, I’ve only just found out that she’d understood the plan differently to me.

If she "understood it differently", then she knew she was going to take accolades for treating the parents while not contributing one red cent.

It's amazing how often that is done and always by people who have a few more people on their side than the other person. They "always" think the bill should be split so they get the meal without all the cost.

Batshittery

KnickerlessFatWoman · 19/07/2026 02:15

XiCi · 18/07/2026 18:31

Exactly this. You agreed to split the bill which is 50/50. When you explained what you had agreed beforehand I thought, this is simple, the bill should be 50/50. I was then a bit confused when you proceeded to say what you had paid. Its therefore no surprise to me that your sister is confused. I think you should pay what you agreed and be more clear in future what youre willing to pay

No, no, NO!!

Read my post properly!!

OP posts:
Mumtobabyhavoc · 19/07/2026 02:16

OP stated: "my sister and I decided this time it was our turn and we were going to treat him (their dad) and our mum instead"

That means sis and OP are splitting the cost of their parents' meal. Nothing else.

OP gave money to cover that plus her own food/drink, and paid £70. It is ludicrous to think one person would contribute towards everyone else's food etc. Why would they?

Using that logic, an even split, everyone should pay toward the £70 for the parents. So, that's £17.50 each for OP, DSis, DBil and DNephew off the top.
The balance, £140 is then £35 each for OP, DSis, DBil, and DNephew.
Everyone, except parents, pays £52.50 each.
OP is then owed $£17.50 as has overpaid. 😝

Get your money back @KnickerlessFatWoman !!! 😉😁

AnnoyedAsAllHeck · 19/07/2026 02:17

TappyGilmore · 19/07/2026 02:11

Um, lots of people expect that? It’s quite common to split a bill 50/50 even though people might have consumed food and drink worth differing amounts, so one party is effectively subsidising another.

I hope none of those people then go around and kvetch about the cost of living. If they have that kind of money to spare they need to just be content. And quiet.

CrazyMidget · 19/07/2026 02:19

lifeturnsonadime · 18/07/2026 13:06

Sorry I misunderstood.

However in my mind if both siblings have agreed to treat parents by splitting the bill then, unless otherwise agreed, then I would think 50% of bill each regardless of the fact that there are are more on their side of the family.

This happens frequently for me / dh as we have less kids than our siblings on both sides. We don't ask the other families to pay more we just split equally.

Well, it sounds as if OP doesn't have a DH or kids, so why on earth should she have to pay half of the total? As she said, there's one of her and three of them. I can't believe her sis thought that going halves on the entire thing was what she meant, or that it's fair. She's a CF who was trying it on.

KnickerlessFatWoman · 19/07/2026 02:19

zephyr148 · 18/07/2026 19:58

Surely as it was a gesture of kindness from both you and your DSis to treat your parents, £70 to £105 wouldn’t make much of a difference? Presumably your nephew, like your BiL, also wasn’t drinking! So overall subsidising you.

Well if £35 doesn’t make much difference, why can’t my sister pay it?

OP posts:
CrazyMidget · 19/07/2026 02:22

KnickerlessFatWoman · 19/07/2026 02:19

Well if £35 doesn’t make much difference, why can’t my sister pay it?

Exactly - the one who has a husband and a dual income.

LoveItaly · 19/07/2026 02:22

I haven’t read most of the replies, but the few I have seen seem to be giving you a hard time.

I would have done exactly what you did, you and your sister treating your parents by splitting their part of the bill between you, and then paying for your own meals. By splitting the whole bill 50/50 you would have been subsidising your sister, which doesn’t seem fair.

Mumtobabyhavoc · 19/07/2026 02:22

KnickerlessFatWoman · 19/07/2026 02:19

Well if £35 doesn’t make much difference, why can’t my sister pay it?

Why did she bitch to your mum about it? Does she have form? (My money says, Yes).
Is she the golden child by chance?

AnnoyedAsAllHeck · 19/07/2026 02:23

KnickerlessFatWoman · 19/07/2026 02:09

But why should I pay more? Why can’t my sister and BIL pay for their own meals?

Correct! It sounds like your BIL knew he would make out like a bandit doing it "his way", as his and his son's meal would be become partly yours to pay.

I just laugh at people like that. You know they would have talked all year about how "they" took their parents to dinner along with you.

I usually don't go out except with my children, etc. I also usually treat (99%), but if I didn't, it would be each person pays their own part so no one feels put upon.

AnnoyedAsAllHeck · 19/07/2026 02:24

Mumtobabyhavoc · 19/07/2026 02:16

OP stated: "my sister and I decided this time it was our turn and we were going to treat him (their dad) and our mum instead"

That means sis and OP are splitting the cost of their parents' meal. Nothing else.

OP gave money to cover that plus her own food/drink, and paid £70. It is ludicrous to think one person would contribute towards everyone else's food etc. Why would they?

Using that logic, an even split, everyone should pay toward the £70 for the parents. So, that's £17.50 each for OP, DSis, DBil and DNephew off the top.
The balance, £140 is then £35 each for OP, DSis, DBil, and DNephew.
Everyone, except parents, pays £52.50 each.
OP is then owed $£17.50 as has overpaid. 😝

Get your money back @KnickerlessFatWoman !!! 😉😁

I admire people who can do this math!
Thank you!

Morepositivemum · 19/07/2026 02:26

The more I think about it the more I see that your sister thought you were saying because it will be expensive we’ll split the bill- ie pay half of the entire bill. I wouldn’t have thought it myself but I think she thought you meant you’d both pay half for ye all to be together

KnickerlessFatWoman · 19/07/2026 02:27

Bournetilly · 18/07/2026 22:22

If your dad usually pays the whole bill and you and your sister agreed to pay instead of your dad I can see why she thought you’d pay 50% each.

I don’t think you are in the wrong but I wouldn’t have included the nephews share, especially since you were drinking wine.

I have explained time and time again that my main was taken off the bill, so it evened out.

Even if you take my nephew out of the equation, there were still two adult meals compared to my one.

OP posts:
CrazyMidget · 19/07/2026 02:31

KnickerlessFatWoman · 19/07/2026 02:27

I have explained time and time again that my main was taken off the bill, so it evened out.

Even if you take my nephew out of the equation, there were still two adult meals compared to my one.

Yes, and the entire point of the exercise was to treat your PARENTS, not to subside your sis and her family. The fact that your dad usually pays for everyone is neither here nor there, in this instance!

Mumtobabyhavoc · 19/07/2026 02:32

AnnoyedAsAllHeck · 19/07/2026 02:24

I admire people who can do this math!
Thank you!

Don't you just hate cheeky people that innocently assume a portion of their meal will be paid for? It seems there's always one like that in every group/family. 🙄

bittertwisted · 19/07/2026 02:33

This is so ungracious
your dad normally pays for everyone, he has saved you both lots of expense
just split the bill, it’s so selfish and Petty, your poor dad deserves more respect

Mumtobabyhavoc · 19/07/2026 02:35

bittertwisted · 19/07/2026 02:33

This is so ungracious
your dad normally pays for everyone, he has saved you both lots of expense
just split the bill, it’s so selfish and Petty, your poor dad deserves more respect

Ungracious to who? The sister and BiL are taking the piss.

CrazyMidget · 19/07/2026 02:35

OneSparklyGoat · 19/07/2026 02:14

Not to the tune of entire extra bodies. We always divide by people and then pay shares.

So BIL and Sis would pay 3 shares plus 1/2 of the parents’s bill.

Only a true cheapskate would expect a single person to pay the same as an entire family.

Edited

You can avoid all this "paying shares" by asking the wait staff to set up separate tabs when you first arrive. Then people are billed according to the desired split, and you don't have to have all this awkwardness. OP actually could have said at the start that one bill should be for her and Mum, and her sister should have said the rest for her, husband, nephew, and Dad. Then no one has to transfer money and there are no conversations about who owes what. Also means you can just enjoy the meal knowing there will be no awkwardness at the end. And this entire situation in this thread can be avoided!

I read about this tip online in a restaurant industry magazine - God knows how I stumbled across the article, but I did. The wait staff in the article were all saying how much easier it is to set up separate billing at the start than separate it at payment. Armed with this new knowledge, I went out with a friend and her family for a meal recently, I clarified beforehand with her that I was paying for myself, not that they were treating me (because she didn't make it clear) and when we got there, I asked the waitress for my bill to be separate. It was bliss, knowing that all the awkwardness had been avoided.

It was a special set menu Sunday lunch, and when she invited me, I responded with "XX pounds for such a nice meal? Sounds good - I can afford that!" This gave her a chance to say "Oh no, it's our treat!" if she was treating me. (I do wish people would be clear!) And she didn't, so - thanks to the article - I knew to ask for a separate tab at the start, not at the end. It worked like a charm. I could order whatever I wanted, knowing it wasn't going to be mixed up with theirs.

AnnoyedAsAllHeck · 19/07/2026 02:39

januaryjanuarydone · 19/07/2026 01:14

The OP probably can’t believe that posters on here are a stupid as her sister. If she had paid any more / paid 50% the treat would have come entirely from her, with no contribution from her sister. How are people not understanding that and saying that the OP is wrong for not either paying for the whole birthday treat or contributing to her BIL/ DN’s meals too?!

Absolutely bonkers.

People that are batshit bonkers is not unusual on MN. In fact, it's a given.

Hopefully, @KnickerlessFatWoman sees enough of us sane people here to know that she is right and they are misguided, if not out and out wrong.

If two separate people are taking two separate people out for a meal, the former two divide the latter two's meals. Then anyone who brought extra people with them, pays for those extra people.

To the person who was so ludicrous to think maybe BIL didn't want to eat there, giving "reason" to why OP should have subsidised his meal....BIL could have stayed home.

CrazyMidget · 19/07/2026 02:50

bittertwisted · 19/07/2026 02:33

This is so ungracious
your dad normally pays for everyone, he has saved you both lots of expense
just split the bill, it’s so selfish and Petty, your poor dad deserves more respect

Considering that her sis and DH are an economic unit of two, and OP is on her own, I disagree. The rellies have a dual income and they split all living expenses. They have two incomes for one home and all fixed expenses, while OP has to pay everything alone...and don't get me started on how often men earn much more than women. Sis having a DH is likely to make a big difference in their economic statuses even with them having a child.

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