nil-rate band (def.)
The amount of your estate that can be passed on free of Inheritance Tax. It is often called the tax-free allowance or threshold.
There is also a residence nil-rate band, an additional allowance that may apply when you leave your home to your children or grandchildren, which tapers away for larger estates.
Whether these allowances apply, and how much of them you can use, depends on your circumstances and on who you leave your estate to. The Inheritance Tax Calculator in My Planning Tools gives you an estimate. For the current figures and the full rules, see HMRC's guidance at https://www.gov.uk/inheritance-tax
adeus does not provide tax advice. If you want advice on your own circumstances, speak to a solicitor or financial adviser.