Leaving money to a grandchild under 18

In England and Wales, a person under 18 cannot generally give a valid legal receipt for a substantial inheritance or manage significant assets themselves. If your will simply gives money 'to my grandchild' without further structure, your executors may need to hold it on a basic trust for them anyway, often without clear guidance on how it should be invested or spent in the meantime.

Setting this up properly in your will, rather than leaving your executors to work it out, gives you control over the age at which the money is released and how it can be used before then.

There is no fixed legal requirement dictating the age a grandchild must reach to inherit; you choose this in your will. Common choices are 18, the age of legal adulthood, 21, or 25, which many people consider a more sensible age for a young adult to receive a significant sum without it being spent impulsively.

You are also free to structure this in stages, for example releasing a portion at 21 and the remainder at 25, or to make provision for trustees to release funds earlier for a specific purpose such as university costs, even before the main age is reached. See our guide on what age children can inherit for more detail on how these age clauses work.

A will trust for a grandchild names trustees, often the grandchild's own parents, other family members, or your own executors acting in that additional role, who hold and manage the money on the grandchild's behalf until the chosen age. Trustees are given power to use the funds for the grandchild's benefit in the meantime, for example towards education or welfare, if your will grants that discretion.

Choose trustees you genuinely trust to act sensibly and in the grandchild's interests, and consider naming at least two, since this is often required practically for administering a trust and provides a helpful check on any single trustee's decisions.

It is worth deciding what should happen to the trust fund if the grandchild dies before reaching the age you set, for example whether it should pass to their own children if they have any, back into your residuary estate, or to their siblings. Without this addressed, the outcome can depend on default legal rules that may not match what you would have wanted.

This is a detail that is easy to overlook but matters in practice, particularly for larger gifts, and a well-drafted will should deal with it explicitly rather than leaving a gap.

If you have several grandchildren, think about whether you want to treat them equally in cash terms, or adjust for age gaps and different needs, since a fixed sum set today may feel very different in real terms by the time a younger grandchild actually reaches the qualifying age. Some grandparents use a percentage of the residuary estate divided equally between grandchildren rather than fixed sums, to keep things proportionate regardless of when the estate is eventually administered.

It is also worth mentioning any large gifts you are planning to make to grandchildren while you are alive, since these can interact with inheritance tax planning and the amount you may wish to leave via your will. See our guide on leaving your estate to grandchildren for wider context on structuring gifts across a family.