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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:
Clavinova · 19/07/2026 11:10

researchers3 · 19/07/2026 10:36

This, although it is very obvious to me that it would be hugely unfair to have split the bill in half!

I can't believe your sister has involved your mum in this when it was her birthday.

I wouldn't bother discussing it tbh, she is so obviously in the wrong and will probably run off to y9ur mum again if you do.

I can't believe your sister has involved your mum in this when it was her birthday.

I suppose that depends on how the conversation between the sister and mother evolved. Were the parents under the impression that the op was paying half of the total bill as well?

Melograno · 19/07/2026 11:12

EstoyRobandoSuCasa · 19/07/2026 11:07

People are so obtuse on AIBU that I can understand why people are tempted to post reverses. I bet if the sister had posted from her point of view, she would have been torn to shreds!

I think they just enjoy arguing and telling people they are wrong and I would pay/ drive a thousand miles, give them all my money so tsk tsk, you are wrong
Its moral narcisissm

Woodfiresareamazing2 · 19/07/2026 11:13

Monty36 · 19/07/2026 10:44

Indeed. The OP agreed to treat mum and dad. Because mum and dad always pay for everyone else when they go out. I doubt mum paid for one child and the other paid for the other. They just paid for the lot.
She and her sister agreed they would pick up the tab this time.
I would have taken that to mean split the bill. And not that one sister pays for one parent and the other pay for the other parent. And the rest is all separate.
But that they would pick up the total restaurant bill together.

"She and her sister agreed they would pick up the tab".

NO!

No, they did NOT agree that!

They agreed they would "treat their parents".

THEY would treat their parents.

Not pick up the tab.

Not split the bill.

Not pay half each of the total bill.

Language matters.

Clavinova · 19/07/2026 11:15

MyOtherProfile · 19/07/2026 11:06

Rude. Not surprising though.

I guess you missed that OPs meal came free because there was an issue. So that evens out the alcohol.

The op chose KnickerlessFatWoman as her username - not me!

I guess you missed that OPs meal came free because there was an issue. So that evens out the alcohol

Totally irrelevant to your post. You posted about previous occasions: "each time" and "usually".

MyOtherProfile · 19/07/2026 11:18

Clavinova · 19/07/2026 11:15

The op chose KnickerlessFatWoman as her username - not me!

I guess you missed that OPs meal came free because there was an issue. So that evens out the alcohol

Totally irrelevant to your post. You posted about previous occasions: "each time" and "usually".

It's ok Clav, I've seen enough of you in action on other threads to understand your position on many things. You don't need to explain.

cubistqueen · 19/07/2026 11:19

This reply has been deleted

Message deleted by MNHQ. Here's a link to our Talk Guidelines.

How rude. My username implies that I’m a royal artist, but I’m very much not.
I suppose that if one’s usernames are supposed to be literal then you would be “cut and paste pointless articles supporting the right wing on all political threads” or, more pithy “Tory bot”

Bellyblueboy · 19/07/2026 11:21

Clavinova · 19/07/2026 11:10

I can't believe your sister has involved your mum in this when it was her birthday.

I suppose that depends on how the conversation between the sister and mother evolved. Were the parents under the impression that the op was paying half of the total bill as well?

Why would the parents care who paid for their grandchildren’s meals and their son in law.

Odd - all they should care about is they were treated to a meal out.

anyone with common sense would understand how unbalanced and unfair splitting the bill would be when one daughter brought two extra people and one daughter came alone.

this thread has totally explained to me how cheeky fuckers get away with things - they just refuse to see logic

Londonisthebestcityintheworld · 19/07/2026 11:21

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?

Very similar thing happened to me. We (DH and I) agreed with my BIL that we would pay for my sister in laws brunch. Party of 4. BUT we split 50:50 and people were still annoyed!! 😂

SIL drank several boozy cocktails at brunch, we had no cocktails. She had two brunch dishes, we each had one. BIL ordered more food than us and shared some of the food SIL ordered. He also had a few non alcoholic cocktails, coffees etc. Sharing as OP included drinking versus non drinking, minors involved. Ordering was very lopsided on our brunch too which makes it harder!

Anyhow, when the bill came we split it 50:50. My DH and his brother. He later said he expected to split it three ways (as we are two people and he is one) and he should have paid 1/3 - that he'd effectively paid for himself and SIL. SIL and BIL are siblings btw, not a couple!

I still don't know what we should have done tbh!

viques · 19/07/2026 11:22

Jk987 · 18/07/2026 13:32

I know what you mean but I think I would have gone halves. Firstly it’s your own young nephew included so you surely wouldn’t mind treating him?

Think of all the times your parents have treated you and you’ve paid nothing? You should think of it as literally splitting the bill paying for individual meals. I’d always want to treat my family and not quibble over a few pounds.

You could equally argue that the sister and BIL ( two incomes)could have covered the OPs ( one income) bill as a treat for her, but that ship has sailed.

However, the sisters agreed to pay for their parents so that the generous parents could enjoy the treat.

Two parents. Two sisters. They each covered the cost of one parents bill.

1sister + 1 parent
1 sister + 1 parent

BIL paid for himself and the child.

1 father + 1 child.

So each working adult paid for two people, ie for a third of the total bill.

Since the OPs main was discounted all three amounts were slightly reduced for all three payees as the OP didn’t get into a “but my main doesn’t count so I am paying less” fight.

Itiswhysofew · 19/07/2026 11:24

You're correct. You halve the cost of your parents between you and your sister.

Clavinova · 19/07/2026 11:26

MyOtherProfile · 19/07/2026 11:18

It's ok Clav, I've seen enough of you in action on other threads to understand your position on many things. You don't need to explain.

Perhaps you have forgotten what you posted - you were clearly referring to previous meals, not the meal last week.

wildnwilde · 19/07/2026 11:28

Dad would usually foot the bill for everyone. I get your point of view entirely but can also understand where the confusion and misunderstanding has come from . She prob thinks we would usually pay nothing but we've offered so let's split the bill 50 /50 . Is it a issue where you will struggle financially cos of it cos I wouldn't be arsed about it tbh with it being a sister. I'd be more inclined to the CF if it was a friendahip group .

Strawberrryfields · 19/07/2026 11:29

I kind of get what you’re saying but the phrase ‘split the bill’ is commonly understood as 50/50.

The present/ treat wasn’t just items of food and drink but the experience of a meal out. Your parents would normally pay 100% so it was paying their usual costs 50/50.

By saying you’re paying for individual food items/ meals you’re not comparing like for like?

Do your parents slip you an extra £50 after every meal out to even things out after paying for your sisters husband and child too? Do you think that’s unfair that her side are getting more? Surely these things all even out in the long run.

However, saying that, as your sister id have offered to pay more to cover bil and son. But they also weren’t drinking so that evens things out a bit.

I’ve no idea why your sister said this to your mum rather than you directly. Cant think how that would’ve come up innocently in conversation. So strange to not just message you if she felt you’d transferred the wrong amount. Which I can understand her thinking seeing as you agreed to split it.

Was it all a set price? How have you got to a neat £35 for everyone? It sounds like you’ve already done some rounding up and down to reach that figure - you can’t just decide all this maths in your head and expect everyone to understand it. Maybe your mums came to 32 and your dads was 41, nephews 15 etc. However, you’ve just worked out the figure of 35 and that’s that? It’s a strange assumption to make. Why not message to explain if that’s what you were going to do.

Have you messaged her to sort it out? You both need to communicate better.

OhLookASquirrrel · 19/07/2026 11:30

You are completely right and I don't understand why people on this thread are piling onto you. I can only presume they are bored and winding you up.

If it was you, your sister, and your parents then splitting the bill in half would be fine. Your sister brought along two extra people in her husband and child so she should be paying for them and one parent and you pay for you and one parent. This is completely fair.

I think your sister (and BIL) are cheeky fuckers to expect you to pay towards their cost. Why should you pay for one parent plus one of their family group? If the bill was split in half then Sister would be paying for her family and you would be paying for both your parents. She would not be contributing towards the 'treat' at all.

Yes it is your sister, and you are all family, but if £35 is not a big deal then why is your sister quibbling over it and getting your mother involved?

I have a similar set up to your family but from the other side. I have a husband and son and my two siblings are single. We go for meals out with our mother and if splitting the bill* there is no way that I would expect to split it between me and my siblings equally. Why should they subsidise my husband and child?

*Husband sometime just pays the whole bill for us as he is a sweetie and we can afford it more than my siblings.

Anyway, you are fine in what you have done. They are CF and you should just ignore their pettiness.

JediNinja · 19/07/2026 11:32

The problem here comes down to how you are interpreting "treating" your parents.

You understand this as "paying for our parents' costs", which is £70 between you two. So with this in mind, you pay your share and half of their costs.

She (and most people on this thread) understands this as "paying for a full bill that they would have otherwise paid", so that is £210 and it would be quite normal to assume you pay that in halves. That is £105 each.

Because you are seeing it as covering only your parents' meal, you see that as you paying for your own meal plus your parents' meal and your sister paying for their own three meals. You are counting transationally, per head, and finding it unfair. The thing is that you sister would not have normally paid £105 for their meals any other day your parents' were paying. Nor you would have paid £35. Your parents would have. By telling your parents you are only covering half of their costs, you are probably making them regret to agree to this "treat", as they had to pass the message, it has put a damper on the dinner meal and the treat is now valued at £70 of their own meal, instead of the £210 of the full meal experience, which is what they usually pay. They treat you all by paying full meals when you meet. You treat them by paying only their meals shared equally.

There's a clear difference on how you understand this treat. Whilst I see your maths and understand the logic, I also think treating them should mean cover the full meal and approached as if it were another gift: 50:50. Just because the treat is to cover the bill, in my opinion, not to cover their meals exclusively. The treat is to have the full family there, enjoy a meal together and not covering that bill.

Next time, specify that you each cover your own costs and divide your parents' costs. This is not what "treat" them would mean for me, though. As the parents don't usually just pay for themselves, in which case yes, you'd be treating them by covering their usual bill. Instead, their usual bill is the full meal for everyone. Treating them would be, to me, to cover that cost between you two. You can indeed bring the logic of actual costs to it, but your parents usually cover the whole cost so a gift to them should also be the whole cost. None of you usually pay anything towards it, so you are both contributing equally. Your stance on paying just half of your parents will make them more reluctant to be "treated", to be honest, as the actual treat is only their servings not the bill.

Bellyblueboy · 19/07/2026 11:34

Strawberrryfields · 19/07/2026 11:29

I kind of get what you’re saying but the phrase ‘split the bill’ is commonly understood as 50/50.

The present/ treat wasn’t just items of food and drink but the experience of a meal out. Your parents would normally pay 100% so it was paying their usual costs 50/50.

By saying you’re paying for individual food items/ meals you’re not comparing like for like?

Do your parents slip you an extra £50 after every meal out to even things out after paying for your sisters husband and child too? Do you think that’s unfair that her side are getting more? Surely these things all even out in the long run.

However, saying that, as your sister id have offered to pay more to cover bil and son. But they also weren’t drinking so that evens things out a bit.

I’ve no idea why your sister said this to your mum rather than you directly. Cant think how that would’ve come up innocently in conversation. So strange to not just message you if she felt you’d transferred the wrong amount. Which I can understand her thinking seeing as you agreed to split it.

Was it all a set price? How have you got to a neat £35 for everyone? It sounds like you’ve already done some rounding up and down to reach that figure - you can’t just decide all this maths in your head and expect everyone to understand it. Maybe your mums came to 32 and your dads was 41, nephews 15 etc. However, you’ve just worked out the figure of 35 and that’s that? It’s a strange assumption to make. Why not message to explain if that’s what you were going to do.

Have you messaged her to sort it out? You both need to communicate better.

Sorry quoted wrong post!!!

Clavinova · 19/07/2026 11:42

Bellyblueboy · 19/07/2026 11:21

Why would the parents care who paid for their grandchildren’s meals and their son in law.

Odd - all they should care about is they were treated to a meal out.

anyone with common sense would understand how unbalanced and unfair splitting the bill would be when one daughter brought two extra people and one daughter came alone.

this thread has totally explained to me how cheeky fuckers get away with things - they just refuse to see logic

Why would the parents care who paid for their grandchildren’s meals and their son in law.

The father usually pays for both.

Perhaps the parents were under the impression that the op was more generous than she is - there has obviously been some confusion all round. Presumably there was no discussion about the actual split of the bill at the meal. I think it's fairly likely the parents also assumed both sisters were paying half of the total bill, hence why the mother passed on the message from the sister.

dick27 · 19/07/2026 11:43

Holy hell I do not understand the abuse you are getting on this. You are 100% correct. Your sis is 100% wrong. Maths appears to be a failing for some. As does fairness. ANY other way of splitting would not be remotely fair. You would be paying the single person premium which very much exists in most scenarios.

MsSquiz · 19/07/2026 11:44

Newyearawaits · 18/07/2026 17:03

And why does that matter?
These are family!

Because the agreement was to treat their parents. The sister isn’t treating the parents by splitting the bill her way, she was just paying for her, her husband and their child

Shinyandnew1 · 19/07/2026 11:44

I’m presuming you know your sister incredibly well-30/40 years maybe of living together, socialising, going out for meals?

Is this a genuine first? Has this come as a total shock that she has interpreted that you’ve suggested splitting a bill one way and she has extrapolated a different way?

Conniecoconut · 19/07/2026 11:46

I absolutely agree with you, I maybe would have phrased it, I'll chip in for mums, you chip in for dad's. My sister is a family of 7 and generally it's just me that goes from my family. I'm not paying for 5 meals if we go out as a 10 when I'm only eating 1. Be cheaper to take your parents out on your own!!

KermitTheToad · 19/07/2026 11:47

If the original conversation was indeed ' we are going to treat mum and dad', then that means that you and your sis pay for your parents between you. @KnickerlessFatWoman Have you not spoken to sis since and explained exactly what you have been saying here? I think Dbil should refund his wife for his and son meal, job done!

Wadsworthy · 19/07/2026 11:48

The present/ treat wasn’t just items of food and drink but the experience of a meal out.

All those who are sayng "Oh it's family, that's the trat. You are mean not to want to pay half."

What about the sister's meanness??? She is expecting her DH and DC to be treated by the OP.

No-one is treating the OP.

See - the single tax in FULL operation.

mounjaroatlast · 19/07/2026 11:49

OP, YANBU. Your words were lets treat our parents, so you did not say you would split the bill.

Your meal wasn't charged for, so you should have paid £35 for one parent, you paid 2 shares to cover alcohols so paid more than enough. Your DS should pay for 4 shares.

Your DS is being a CF if she is expecting you to pay for her family as well.

It's said how so many people on here can't see that you did not say 50/50 and that if it had been that, you would have paid for both your parents and your DS only for her own family.

Savvysix1984 · 19/07/2026 11:52

I agree with you op.
I have a brother who is single. I’m married with one dc. When we took DF out for Father’s Day, we agreed we would cover both mum and dad. My brother paid a 3rd (roughly) and I paid 2/3.
if he’d only paid for himself he’d have paid 1/6 and I’d have paid 1/2 and my parents 2/6. I also threw in the tip separate as cash.

it does annoy me that single people often get a raw deal. We try and be fair around joint presents for parents at Xmas too. I’ll always pay more so my brother pays less as I’m in a two income household and even as a single person I earn more than double he does.

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