The figure has risen by £58 million compared to last year, according to unbiased.co.uk.
Researchers from the website said not putting the policy under trust could reduce a £100,000 life insurance pay out by as much as £40,000 if an individual's estate is worth more than £325,000, leaving a loved one at risk of a sizeable tax bill.
With rising house prices and an improved economy set to leave more and more taxpayers exceeding the £325,000 inheritance tax-free threshold set by the government, unbiased.co.uk and Prudential have launched what they described as "an easy-to-follow checklist" of what to consider when IHT planning, including understanding the value of an estate, gifting to loved ones and getting advice.
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The website's studies have revealed only 27% of consumers would be confident in tackling inheritance tax planning without the help of a professional financial adviser.
Karen Barrett, chief executive of unbiased.co.uk, said: "Many of us want to pass on our estate to loved ones after we're gone but what people don't realise is the sizeable tax bill we might also be handing over in the process.
"As the housing market continues to boom and the IHT threshold remains static, this leaves many more of us at risk of passing on an unnecessary tax bill.
"Planning ahead can mean your beneficiaries don't pay more tax than they need to as there are many strategies for reducing an inheritance tax bill including wills, pensions, trusts and other tax advice.
"We have designed our checklist to provide a simple step by step guide for people to help them tackle their inheritance tax planning head on."
Les Cameron, head of technical at Prudential, said: "It is often said that inheritance tax is a voluntary tax due to the number of different ways it can be avoided.
"However, Government statistics show that the amount of tax paid and number of families affected has been increasing over the last few years.
"There are several possible approaches and a wide range of solutions available to help people maximise the amount of wealth they pass on to their loved ones.
"IHT planning can range from the relatively straightforward to the very complex.
"Given the variety of strategies and solutions available I would always recommend seeking professional advice."