The sum represents money Germany saved through lower interest payments on funds the government borrowed amid investor "flights to safety", the study said.
"These savings exceed the costs of the crisis -- even if Greece were to default on its entire debt," said the private, non-profit Leibniz Institute of Economic Research in its paper.
"Germany has clearly benefited from the Greek crisis."
When investors are faced with turmoil, they typically seek a safe haven for their money, and export champion Germany "disproportionately benefited" from that during the debt crisis, it said.
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Germany, the eurozone's effective paymaster, has demanded fiscal discipline and tough economic reforms in Greece in return for consenting to new aid from international creditors.
Finance Minister Wolfgang Schaeuble has opposed a Greek debt write-down while pointing to his own government's balanced budget.
The institute, however, argued that the balanced budget was possible in large part only because of Germany's interest savings amid the Greek debt crisis.
The estimated 100 billion euros Germany had saved since 2010 accounted for over three percent of GDP, said the institute based in the eastern city of Halle.