"The total losses for the insurance industry are estimated between $3.5 and $4.5 billion," the company said in a statement, adding that its portion of the bill would be around $300 million.
Swollen rivers caused deadly floods in the eastern part of Germany, the Czech Republic, Austria, Hungary and Slovakia in late May and June, killing at least 19 people, forcing thousands to evacuate and destroying property and crops.
The total insurance bill estimated by Swiss Re was lower than estimates by ratings agency Fitch, which last month cautioned the deluge could be more costly than the "worst-in-a-century" floods in 2002.
It forecast €12 billion in damage in Germany alone, of which up to €3 billion euros would be covered by insurance policies.
Swiss Re; meanwhile; welcomed the fact that local flood prevention measures had spared many regions from large losses, as in Prague, where mobile flood barriers saved most of the city from significant flooding.