Most guides compare a Junior ISA against a children’s savings account. That’s not actually the choice a lot of parents are weighing. If you’ve got money left in your own £20,000 ISA allowance, the real question is simpler: open a Junior ISA for your child, or just put the extra away in your own ISA and let them have it later. The answer depends on your tax position more than anything else, and it’s worth working through properly before you decide rather than defaulting to whichever product you’ve heard of first.

Junior ISA vs saving in your own ISA: the real comparison

A Junior ISA belongs to your child from the moment you pay in. It’s locked until they turn 18, at which point it becomes theirs to do with as they like. You can put in up to £9,000 a year, split however you want between cash and stocks and shares, and everything inside it grows completely tax free.

Money kept in your own ISA works differently in almost every way that matters. It stays legally yours. You can spend it, move it, or change your mind at any point between now and whenever you decide to hand it over. It also grows tax free, same as the Junior ISA, but it sits inside your £20,000 personal allowance rather than the child’s separate £9,000 one.

	Junior ISA	Your own ISA
Who owns the money	The child, from the day it’s paid in	You
Access before 18	None	Any time
Allowance used	Child’s £9,000	Your £20,000
Tax on growth	None	None
What happens at 18	Becomes the child’s adult ISA automatically	Stays yours unless you give it to them

Neither option is wrong. A Junior ISA ring-fences the money and guarantees it reaches your child intact. Your own ISA keeps your options open, which matters more than people expect once life gets in the way of the plan you had ten years ago. If you’re also weighing this against Premium Bonds or a pension for your child, we’ve compared those separately too.

Why the £100 rule might not even apply to you

Every Junior ISA guide mentions the £100 rule, usually as the reason to avoid a normal savings account. Here’s the part most of them skip: whether it actually affects you depends on your Personal Savings Allowance, and that’s easy enough to check.

The rule itself is specific. If you give your child money and it’s sitting somewhere other than a Junior ISA, and it earns more than £100 in interest in a tax year, the whole amount gets taxed at your rate, not theirs. That’s £100 per parent, so £200 between a couple. It only applies to money from parents and step-parents. Grandparents, aunts, uncles and friends are exempt entirely, however much they give.

But your Personal Savings Allowance sits on top of that rule, and I think this is the bit that trips people up most. A basic-rate taxpayer can earn £1,000 in savings interest a year before paying any tax at all. Higher-rate taxpayers get £500. Additional-rate taxpayers get nothing. If the interest from money you’ve given your child, added to everything else you earn in interest, stays under your allowance, the £100 rule technically applies but has no practical effect. You wouldn’t owe anything either way.

Where it does bite is if you’re already close to or over your allowance from other savings and investments. In that case, every extra pound of interest from a child’s account counts against you, and a Junior ISA sidesteps the problem completely because nothing inside it is taxable in the first place. It’s worth actually doing this sum for your own situation rather than assuming the £100 figure applies to you just because it’s the number everyone quotes.

Three questions to work out which is right for you

Start with whether you’re likely to use your full Personal Savings Allowance this year, once you count in any interest from money you’ve given your child. If you are, a Junior ISA avoids the problem outright. If you’re comfortably under your allowance, it’s less urgent, and the tax argument for a Junior ISA weakens considerably.

Then check whether you’ve still got headroom in your own £20,000 ISA allowance. If you’ve already used it up elsewhere, a Junior ISA gives you extra tax-free space rather than competing for the same pot you’re already stretching thin.

Last, think about whether you’d ever want access to this money before your child turns 18, for a house deposit, an emergency, or just because plans change. A Junior ISA removes that option completely, no exceptions. Your own ISA doesn’t.

If your answers point in different directions, that’s normal, and it’s more common than picking cleanly one way. It usually means splitting the money between both makes more sense than committing everything to a single account.

Two examples: same £50 a month, different outcomes

Say two parents each put £50 a month aside for their child. To keep the maths simple, both examples use an illustrative rate of 4% AER rather than a specific product’s actual rate, since the point here is how the tax rules interact, not which provider pays the most.

The first is a basic-rate taxpayer with plenty of room left in her own ISA allowance. She isn’t close to her £1,000 Personal Savings Allowance even with this extra interest included. Putting the £50 into her own ISA costs her nothing in tax, and she keeps the flexibility to redirect it if something comes up before her daughter turns 18.

The second is a higher-rate taxpayer who’s already used most of his own ISA allowance on other savings. Adding £50 a month in his own name would push him over his £500 allowance within a couple of years, at which point the interest becomes taxable at his rate. Paying it into a Junior ISA instead avoids that entirely and doesn’t touch his personal allowance at all.

Same contribution, same goal, different answer. What decides it isn’t the £50 a month, it’s what’s already happening in the rest of each parent’s finances.

What you give up if you keep it in your own name

The tax side gets most of the attention, but it isn’t the only thing at stake. Money in your own name is legally yours, which cuts both ways. If you’re ever declared bankrupt, it could be treated as one of your assets. If you divorce, it forms part of the pot to be divided, regardless of your intention to eventually give it to your child. If you die before you’ve passed it on, it’s dealt with under your estate rather than automatically going to them.

A Junior ISA sidesteps all of this because the money is the child’s from the moment it’s paid in. Nobody but them can access it, and nothing that happens in your finances afterward can touch it, whatever that turns out to be.

I’d put this lower down the list for most parents. It’s easy to fixate on a scenario that’s statistically unlikely to affect you specifically, and if your finances are stable and the amounts are modest, it’s a small risk worth accepting for the flexibility. But if you’re setting aside anything substantial, or your circumstances feel genuinely uncertain, it’s worth weighing this alongside the tax question rather than as an afterthought once you’ve already decided.

Frequently asked questions

Are Junior ISAs worth it if I don’t pay tax on my savings interest anyway?

Not necessarily. If you’re well under your Personal Savings Allowance and don’t need the money locked away, saving in your own name costs you nothing extra in tax and keeps your options open. A Junior ISA becomes more useful once you’re close to using up your allowance elsewhere.

Can I save in my own name and open a Junior ISA at the same time?

Yes. There’s nothing stopping you from doing both. Many parents split contributions, using a Junior ISA for the portion they want locked away and their own ISA for money they might want access to later.

What happens if I’ve already used my full £20,000 ISA allowance this year?

A Junior ISA gives you an extra £9,000 of tax-free headroom that’s entirely separate from your own allowance. If you’re paying tax on savings interest and have no room left in your own ISA, this is usually the point where a Junior ISA starts to make more sense.

This is general information, not financial advice. Everyone’s tax position is different, so if you’re not sure how the Personal Savings Allowance applies to you, it’s worth checking with a financial adviser. Read more about what a Junior ISA is, or how it compares to a dedicated children’s savings account. Ready to get started? You can begin opening a Junior ISA in a few minutes.