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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

Original poster

To think "half your age plus seven" is a massive pile of nonsense?

370 replies

TransportNerd · 01/07/2026 08:07

Mumsnet seems to take a very dim view of age gap relationships, far more so than I think the general population does. I've seen plenty of age gap relationships work just fine.

Every single time they're discussed here, though, someone wheels out the "rule" that you shouldn't date someone younger than half your age plus seven years.

People treat it like it's absolutely set in stone, and that breaking this "rule" is some sort of disgusting taboo. I've even seen someone argue it should be enshrined in law, with penalties for those who break it.

Personally, I've always thought it was complete nonsense. It was simply something in a French novel in the early 1900s. It doesn't really take anything important into account, and ignores the principle that consenting adults can do what they like.

Quite apart from anything else, why is it plus seven? Why not five, eight or ten? I'm sure it's only seven because that's a number that's had mystic significance since ancient times. Not a good basis for making laws!

Anyway:

YABU - yes, it's a rule and shouldn't be broken
YANBU - it's a big pile of nonsense and doesn't mean anything

OP posts:
Didimum · 01/07/2026 10:10

Glowingup · 01/07/2026 09:56

So it doesn’t align at all with how you feel about age gaps because like you say, 60 and 37 is quite off and most people would raise an eyebrow. I also think 50 and 32 is a pretty massive age gap. It is also strange because there’s little difference between 60 and 37 and say 60 and 34 but according to this weird “rule” one is fine and one isn’t. And again, little difference between 50 and 32 (apparently acceptable) and 50 and 30 (apparently a no-no).

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I’d still say it broadly aligns, certainly.

GreenCaterpillarOnALeaf · 01/07/2026 10:10

I think a lot of women on here have had bad experiences with older men. I have and it does taint my view a little, but I try to keep an open mind and think of it in terms of where the people are in life. A 25 year old woman who runs a (successful) business and has worked since she was 16 and an older bloke have less of a power imbalance than a 25 year old woman who still lives at home or works in Tesco.

Maybe this is wrong, but I tend to care less when the woman is older. I know loads of woman who have been traumatised by older men and I don’t know any men who’ve been traumatised by older women. Most of the men I know who date/have dated older women sing their praises.

OneFineDay22 · 01/07/2026 10:07

TransportNerd · 01/07/2026 09:48

I did have, they're in their 20s now.

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How would you feel if one of your friends started a relationship with one of them? Preferably, a friend who has known them since they were little. Not illegal…

Lou7171 · 01/07/2026 10:05

Cakeandcardio · 01/07/2026 10:05

Most of what people say on this site is nonsense.

Valid point 😂

Cakeandcardio · 01/07/2026 10:05

Most of what people say on this site is nonsense.

bridgetreilly · 01/07/2026 10:04

I’ve never heard anybody say it should be the law. That’s nonsense.

StationJack · 01/07/2026 10:04

@MrsShawnHatosy , You fitted the rule the OP dislikes, though. Had you been 21 and him 39, you wouldn't have.

SpaceRaccoon · 01/07/2026 10:03

The “half your age plus 7 rule” is a good way of deterring age imbalanced relationships from even starting. No bad thing in my opinion.

It isn't a rule though. It's just a thing people say.

LondonLass2026 · 01/07/2026 10:01

I've dated men exactly my age and they all ended horribly. I dated a few years younger - ended horribly.

I am currently with someone around 10 years younger, and it's worked so far but we have had some wobbles lately. But I truly think that would happen whatever the age.

It's actually really hard to share your life with one person and to try and see eye to eye all the time. But I don't think age gaps have that much of a bearing - why would they, really?

MrsShawnHatosy · 01/07/2026 10:00

WillThingsEverBeFergaliciousAgain · 01/07/2026 08:16

Age gaps when one is under the age of 30 and one is over is very different from both being over 30 imo.

I was 28 and DH was 39 when we met. We’ve been happily married for 36 years.

Ohthisheat · 01/07/2026 09:59

Ohcrap082024 · 01/07/2026 08:18

As the mother of teens, I think it’s a pretty good rule of thumb. So when my dd was telling me about a 16 year old dating a 13 year old, we used the rule to explain why that’s not appropriate.

16 and 15 is fine. 16 and 13 is not.

Edited

I think it works well for teen/early twenties relationships. Older than that, it's nonsense.

OneFineDay22 · 01/07/2026 09:58

GasPanic · 01/07/2026 09:45

I don't agree with giving 16 year olds the vote because I don't believe they are as a cohort are mature enough.

I wouldn't go out with anyone under about 30 because I doubt that I would have that much in common with them otherwise. But what I personally would and wouldn't do is completely irrelevant to the discussion.

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I think it’s relevant. If, for example, 99% of people were to say no, one would wonder what’s going on with that 1% that apparently doesn’t see the problem.

Lou7171 · 01/07/2026 09:57

TempestTost · 01/07/2026 09:50

This would suggest 19 yos shouldn't have relationships at all.

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No it doesn't.

Glowingup · 01/07/2026 09:56

Didimum · 01/07/2026 08:13

I only ever heard people refer to it casually, and never heard it taken seriously. And of course we’re aware there are no hard and fast rules in it.

I have to say though, the maths has always aligned with how I tend to feel internally about age gaps. Though gets less palatable the older you go – 60 and 37 begins to sound a bit off.

Edited

So it doesn’t align at all with how you feel about age gaps because like you say, 60 and 37 is quite off and most people would raise an eyebrow. I also think 50 and 32 is a pretty massive age gap. It is also strange because there’s little difference between 60 and 37 and say 60 and 34 but according to this weird “rule” one is fine and one isn’t. And again, little difference between 50 and 32 (apparently acceptable) and 50 and 30 (apparently a no-no).

StationJack · 01/07/2026 09:55

I'm sure there sensible and mature people in their 20s are but you change a lot between 19 and 29.

A 28 yr old dating a 21 yr old matches the rule.
a 56 year old dating a 35 year old matches the rule.

Additup · 01/07/2026 09:55

TempestTost · 01/07/2026 09:50

This would suggest 19 yos shouldn't have relationships at all.

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No it doesn't. It's suggests 19 year olds are probably better off learning about relationships with others a similar age rather than some old enough to be their parent.

shockthemonkey · 01/07/2026 09:54

"Are you the creepy 40 year old who has brainwashed my 19 year old niece? It sounds like something he would say (and she would parrot)."

It'd be weird if they did parrot the rule, seeing as they are breaking it! He would not be able to date anyone under 27. And yet there he is with a 19-year-old.

TempestTost · 01/07/2026 09:50

Lou7171 · 01/07/2026 09:21

Glad it worked out for you but my main concern is that at 19, people are still developing and often lack life experience to navigate a relationship. I was a completely different person at 19 compared to 25. I tend to view these relationships through the lens of potential exploitation rather than individual success stories. I wouldn't want this for my daughter.

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This would suggest 19 yos shouldn't have relationships at all.

Ohcrap082024 · 01/07/2026 09:48

TransportNerd · 01/07/2026 08:21

But there's already a law for age of consent, that's well reasoned and sensibly applied. Why use some made up nonsense instead of what's actually properly in place?

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Indeed. But relationships between teens don’t tend to start off as sexually intimate so the consent argument tends to come into play further down the line. There can be monthd of online talking, seeing each other etc before a relationship becomes boyfriend and girlfriend.

The “half your age plus 7 rule” is a good way of deterring age imbalanced relationships from even starting. No bad thing in my opinion.

Original poster
TransportNerd · 01/07/2026 09:48

OneFineDay22 · 01/07/2026 09:43

Do you have teenage children?

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I did have, they're in their 20s now.

OP posts:
GasPanic · 01/07/2026 09:45

OneFineDay22 · 01/07/2026 09:40

How old are you and would you go out with a 16 year old? The government wants to give them the vote because they’re easy to manipulate - the opposite of being able to think for themselves properly about the future.

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I don't agree with giving 16 year olds the vote because I don't believe they are as a cohort are mature enough.

I wouldn't go out with anyone under about 30 because I doubt that I would have that much in common with them otherwise. But what I personally would and wouldn't do is completely irrelevant to the discussion.

LindorDoubleChoc · 01/07/2026 09:45

Jellybunny98 · 01/07/2026 09:38

My husband & I are the same age so I have no skin in the game but I think age gap relationships are most tricky sort of pre-30 and then later in life. A 15 year age gap at 17 and 32 just feels icky, massively different stages of life, at 30 and 45 it probably doesn’t feel like much of an age gap at all, but then at 45 and 60 again it starts to feel like a huge gap. My aunt and uncle have a 15 year gap and now he is 70 she often says she feels the age gap more than she ever has because while she still feels young at 55 she now feels she is married to an old man.

No shit Sherlock. And your Aunt didn't have the nous to foresee this? My best friend is 9 years younger than her husband and, partly because of their extreme extrovert/extreme introvert personalities, the age gap now seems vast.

OneFineDay22 · 01/07/2026 09:43

TransportNerd · 01/07/2026 09:41

Well, yes, actually.

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Do you have teenage children?

Original poster
TransportNerd · 01/07/2026 09:41

OneFineDay22 · 01/07/2026 09:38

So someone the same age as a teacher could have a relationship with a 17 year old and that would be fine, because the law says so….

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Well, yes, actually.

OP posts:
OneFineDay22 · 01/07/2026 09:40

GasPanic · 01/07/2026 09:39

After you reach the age of 18 you are free to make your own decisions in life.

Who you decide to have relationships with is no one else's business. I don't spend my time wondering whether other peoples relationships are appropriate because it's got nothing to do with me.

It's probably worth pointing out that the current government wants to give 16 year olds the vote.

Apparently they are old enough to make decisions about the future of the country. But according to many they are not old enough to make good judgement decisions on their own futures.

How old are you and would you go out with a 16 year old? The government wants to give them the vote because they’re easy to manipulate - the opposite of being able to think for themselves properly about the future.

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