Ditching sterling in favour of a Scottish pound would cost the average household 20% of their income, it has been estimated.
The SNP government announced last month that following a vote for independence it plans to introduce a new currency.
Analysis suggests it would be quickly devalued against sterling by as much a 20-30%, immediately taking money out of household pockets and raising the cost of doing business.
The claim is published today on ourmoney.scot, a new website founded by currency specialist Prof Ronnie MacDonald in association with the pro-union group Scottish Business UK (SBUK).
The website provides visitors with a tool to discover exactly how much they would be affected according to their income.
It sets out how it believes the introduction of a new Scottish currency would hike the cost of imports, increase debt costs and lead to higher interest rates. Households which a current net income of £35,000 a year – the Scottish average – would see their spending power slashed by the equivalent of £7,300.