European governments hurried Monday to calculate how many hundreds of billions of euros they will spend on an unprecedented 15-nation plan to save banks. That plan, along with action by top central banks to pump credits into the financial system, already appeared to be soothing markets.

Governments of Germany, France, Italy and Austria were on Monday deciding the details and putting a price tag on the plan announced the night before at an emergency summit in Paris. France's Le Monde daily estimated the total European burden at a staggering €1.3 trillion ($1.77 trillion).

France capped its commitment to the bank rescue plan at €360 billion ($491 billion).

In Europe's most unified response yet to the financial crisis, leaders of the 15 countries that use the euro currency agreed Sunday that individual governments would guarantee bank refinancing until the end of next year, rescue important failing banks through emergency cash injections and take other swift measures to encourage banks to lend to each other again.

Stocks markets rebounded Monday after the European decision and other weekend efforts to find solutions to the financial crisis, which has crushed major banks in both the U.S. and Europe and battered stock exchanges worldwide. Additionally, some short-term euro interest rates fell in a sign the measures may be having an effect on troubled credit markets.

Germany's benchmark index DAX jumped 6.44 percent to 4,836.88, France's CAC40 was up 6.47 percent at 3,382.01, while Britain's FTSE100 rose 4.82 percent to 4,121.73. Also helping markets was a joint move by the U.S. Federal Reserve, the European Central Bank and the Swiss National Bank to provide unlimited short-term credit in U.S. dollars to financial institutions. The Bank of Japan said it was considering similar measures.

Although European governments pledged to let any bank fail, there is no common European fund for this rescue plan — the money is pledged by individual governments, so that no one country has to pay for the choices of the other ones.

Europe's biggest economy, Germany, put together a rescue package worth a total of as much as €500 billion ($671 billion) to shore up the country's financial system, according to the Finance Ministry. Spain said it would guarantee up to €100 billion ($135 billion) in bank bond issuance this year.

The head of the International Monetary Fund welcomed the European decision despite the high price it is expected to impose on state budgets.

"We must recapitalize the banks ... otherwise everyone will suffer," Dominique Strauss-Kahn said on France's Europe-1 radio Monday. "And that costs money."

The euro zone leaders who met Sunday have yet to sell their packages to voters at home, and analysts warned that governments and legislators could still balk. The overall cost will be heavy, especially on countries already in or on the brink of recession.

"It is a huge amount," Volker Kauder, parliamentary leader of German Chancellor Angela Merkel's conservative bloc, told ARD television Monday.

"We are assuming ... that the banks will regain trust in one another and will start lending to each other again," he said.

French daily Le Monde reported the estimated cost to France's government alone at €300 billion ($407 billion), without providing sources or explanations for its calculations.

French President Nicolas Sarkozy, German Chancellor Angela Merkel and Austrian Chancellor Alfred Gusenbauer planned simultaneous announcements Monday afternoon after their governments separately finalize details of their own spending. Italy's government was also meeting Monday to discuss its part of the package.

Portugal's government has already announced it would provide guarantees of 20 billion euros ($27 billion) — nearly 12 percent of annual GDP — for Portuguese inter-bank lending.

The European moves are modelled on Britain's 50 billion-pound ($88 billion) plan to partly nationalize major banks and promises to guarantee a further 250 billion pounds ($438 billion) worth of interbank loans to restore confidence in the financial sector.

Analysts from the banking sector generally saluted the euro zone measures. "After a haphazard start, Europe is finally getting its act together," Bank of America said in a research note Monday. "The size and nature of the national plans suggest that they could finally make a difference."

In another note, Unicredit said, "European policymakers are now racing ahead of the US in their efforts to solve the crisis."

The rest of the 27-member EU will have a chance to sign up to the euro-zone measures when they meet Wednesday.

Already, countries outside the euro zone were taking steps on their own.

Poland's government was meeting Monday to assess the euro bailout package, and Poland's central bank was preparing a package to try to build confidence in the country's banking sector.

Norway, also outside the euro zone, said it plans to offer new government bonds worth 350 billion kroner ($55.4 billion) to banks to help improve liquidity in the market.

In Sweden, Finance Minister Anders Borg said Monday that the government plans to put forward a draft law Wednesday to guarantee new bank debt until the end of 2009 and support banks with added share capital.