On gov.uk
Interest on savings for children
You can invest in a tax-free account for your child, like a Junior ISA or Child Trust Fund. This means tax won’t be deducted from the interest.
Other accounts
For other children’s accounts, there’s usually no tax to pay unless the child:
gets more than £100 in interest any tax year (6 April to 5 April) from money given by a parent
has an income over their personal tax allowance of £10,000, eg a trust
Banks and building societies automatically deduct tax from interest on these accounts at the basic rate of 20%. You can ask them not to do this for your child’s account by filling in form R85.
Reclaim tax
If tax has already been deducted, fill in form R40 and send it to HM Revenue and Customs (HMRC). It takes about 6 weeks to get a refund.
HMRC
Leicester & Northants (Claims)
Saxon House
1 Causeway Lane
Leicester
LE1 4AA
If your child gets more than £100 interest
You need to tell HMRC if your child makes more than £100 in interest from money given by one parent, or more than £200 if given by 2 parents.
The interest should be taxed at the rate the parent pays on their own savings interest.
Example
As a parent you save £5,000 in your child’s account with interest of 2.5%, your child will make £125 in interest. The interest is more than £100, so if you’re a basic rate tax payer, tax should be deducted at 20%.
The £100 limit doesn’t apply to money given by grandparents, relatives or friends.