Mr Swinney told the SNP conference the Scottish economy already outperforms that of the UK as a whole, and would do even better if the country became independent.
He added the consequences of a No vote in the independence referendum next year would be costly.
It came as Treasury spokesman Stewart Hosie criticised the Coalition Government after a leading civil servant warned that Britain may not meet David Cameron's pledge to make the UK one of the world's five leading business-friendly nations.
Mr Hosie spoke out after The Herald yesterday reported Martin Donnelly's warning that rapid progress is required in a range of areas before the Prime Minister's goal can be realised. Mr Donnelly works for the Department for Business Innovation and Skills.
The SNP MP said: "Westminster's failings have seen the UK tumble down the rankings when it comes to supporting businesses and economic recovery.
"The Westminster Government has lost whatever semblance of a grip it had on what is happening in the UK economy.
"This sorry track record of failure stands in stark contrast to the success with which the SNP Government has attracted businesses to Scotland and created jobs.".
Meanwhile, Mr Swinney hit out at the "reckless deficits Westminster has built up", saying that "every person in Scotland is paying the bill, paying the price, for Westminster's mismanagement".
In his speech, he attacked the UK Government for "five years of austerity, with another five years of austerity to come" and said Chancellor George Osborne has failed to solve the country's economic problems. "The UK hasn't paid down the deficit and household incomes have fallen. The UK deficit is now £121 billion," he said.
The "economic performance of Scotland is better than the UK" with a higher employment rate and lower unemployment rate, he said as he highlighted recent GDP figures which show that growth in Scotland "outstripped" that of the UK, at 1.8% compared with 1.3%.
"That is what we are able to do with devolution," Mr Swinney said.
"We could do so much more with independence.
"The debate over Scotland's wealth has been won. Scotland can afford to be independent. The facts and figures are clear and they are indisputable. Scotland is in a stronger financial position than the UK."
As well as attacking the coalition's handling of the economy, he described UK Government welfare reforms as "punishment for the vulnerable".
The Scottish Government has provided £20 million to help mitigate the effects of housing benefit cuts, known as the "bedroom tax".
Cash from the Scottish Government and local councils has been used to prevent half-a-million people from suffering a 10% cut in council tax benefit, he said.
"We go the extra mile to pick up the pieces from bad Westminster decisions," Mr Swinney said.
"Never has that been more the case than on the welfare reform programme."
He said "those who can work should work" but "let me also be clear that in an independent Scotland we will help our young people into work not humiliate them, and we will support our vulnerable people into work not vilify them into work".
Opponents of independence like to claim that, if the country left the UK, its economy would be based on oil, but Scotland's strength is also in its people, he said.