Married couples can pass on up to £1 million tax-free if they plan their estates carefully.

The Inheritance Tax  (IHT) nil-rate band is currently £325,000. This means there is normally no IHT to pay if an estate is valued below this threshold. This amount can be higher if you leave everything above the £325,000 threshold to your spouse, civil partner, a charity or a community amateur sports club.

In addition, there is an IHT residence nil rate band (RNRB) of £175,000. This is a transferable allowance for married couples and civil partners (per person) when their main residence is passed down to a direct descendent such as children or grandchildren after their death. The allowance is available to the deceased person’s children or grandchildren.

Any unused portion of the RNRB can be transferred to a surviving spouse or partner. The RNRB is in addition to the £325,000 nil-rate band. The allowance is available to the deceased person's children or grandchildren. Taken together with the current IHT limit of £325,000 this means that married couples and civil partners can pass on property worth up to £1 million (£325,000 x 2 plus £175,000 x 2) free of IHT to their direct descendants. 

The transfer does not happen automatically and must be claimed from HMRC when the second spouse or civil partner dies. This is usually done by the executor making a claim to transfer the unused RNRB from the estate of the spouse or civil partner that died first.

There is a tapering of the RNRB for estates worth more than £2 million even where the family home is left to direct descendants. The additional threshold will be reduced by £1 for every £2 that the estate is worth more than the £2 million taper threshold. This can result in the full amount of the RNRB being tapered away.