As much as £175m goes missing each year, as 170,000 people have struggled to track down the assets left by loved ones in the last 10 years.
On average people fear they have missed assets worth £9,700, while 12% think they failed to claim more than £20,000.
Stephen Foden of Willsandassets.co.uk said: “No one wants to think about what will happen when they die but failing to do so can leave loved ones with significant problems and stress at an already very tough time.
“With more than 175,000 people a year struggling to sort out loved ones’ finances there is clearly a need for better planning and our service provides a single secure place to store wills and to detail what financial assets there are and how they can be found.”
One of the problems is drawing up wills, as under half (49%) have them.
This rises to 79% for over-65s, but of that demographic only 36% have had them updated within the last two years.
Tracking down assets can be expensive, as according to research from willsandassets.co.uk 39% of those who have lost loved ones in the past 10 years have spent an average £2,250 on solicitors and other advisers after a death.
Willsandassets.co.uk has launched an online national registry providing a single secure place for people to store wills, final instructions and details of their assets to make it easier for loved ones after a death.
The service is free for registering wills and charges £12 a year for those who wish to store details of assets and update them regularly.