What is the difference between a will and probate?
A will is a document. Probate is a process. One says what should happen; the other is the legal authority to make it happen.
A will is a legal document setting out who inherits what, who should administer the estate (the executors), and often who should look after any children. In England and Wales it must be in writing, signed by the person making it, and witnessed by two people who are not beneficiaries — a witness who inherits loses their inheritance, which catches people out.
Probate is the court process confirming a will's validity and granting the executors legal authority to deal with the estate. The document issued is a grant of probate. Banks, share registrars and the Land Registry will generally not release or transfer significant assets without sight of it.
When there is no will, the rules of intestacy decide who inherits, and someone applies for letters of administration instead — the same authority under a different name.
Probate is not always required. Small estates below a bank's own threshold, assets held as joint tenants (which pass automatically to the survivor outside the estate), and jointly held bank accounts often pass without it. Property held as tenants in common does not pass automatically and normally requires probate.
Why probate takes so long. Executors must identify all assets and debts, value the estate, deal with HMRC and pay any inheritance tax before the grant is issued — which creates the awkward position of needing money from the estate to unlock the estate. Straightforward cases commonly take six to twelve months; contested or complex ones far longer.
Executors are personally liable for distributing correctly, which is why they are cautious.
This is general information about England and Wales. Scotland uses different terminology and procedure. Take professional advice on a specific estate.