The countries further pledged $3.73 billion in aid for 2018-20 at the Brussels meeting, which was co-chaired by the European Union and United Nations and follows a conference in London last year which raised $12 billion (10.1 billion euros).
"Our conference is sending a powerful message, we are not letting down the people of Syria," EU Humanitarian Aid Commissioner Christos Stylianides told delegates.
Announcing the new pledges to applause from those at the meeting, he added: "Thank you so much. It is an impressive figure."
Stylianides did not clarify if the funding was new, or if it included some funds previously pledged by the international community for war-torn Syria.
In London last year, donors put together two $6.0 billion tranches in aid, one for 2016 and the other to cover the period to 2019.
The two-day Brussels meeting brought together some 70 countries and aid groups who also wanted to show support for UN-sponsored peace talks between the rebels and Russian-backed President Bashar al-Assad.
Wednesday's session was dominated by news that at least 72 civilians including 20 children had been killed in a suspected chemical weapons attack on the rebel-held town of Khan Sheikhun in Idlib province.
- 'War crimes in Syria' -
"The horrific events of yesterday demonstrate unfortunately that war crimes are going on in Syria," said UN chief Antonio Guterres.
"This conference must represent a moment of truth where the international community" finally comes together to settle the war and give the Syrian people hope, he said.
British Foreign Secretary Boris Johnson told delegates it was "impossible for us to ignore the horrific attack" and pointed the finger of blame firmly at Damascus, as the US ambassador to the United Nations, Nikki Haley, warned of unilateral American action.
Johnson and other delegates in Brussels repeatedly urged all parties to the conflict and their backers to condemn the attack and the use of chemical weapons.
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The war has claimed more than 320,000 lives since anti-Assad protests descended into a full-blown civil war in 2011, with five million Syrians fleeing the country and most of the remaining population being displaced.
Most of the refugees have ended up in Turkey, Lebanon and Jordan.
The UN warned Tuesday that the plight of the refugees was becoming "desperate", with only 433 million euros out of a needed 4.7 billion euros pledged so far.
The UN estimated another 3.4 billion euros was needed for humanitarian aid in Syria.
- 'Ticking time-bomb' -
Lebanese Prime Minister Saad Hariri urged donors to "invest in peace".
"Ladies and gentlemen, the current situation in Lebanon is a ticking time-bomb," he told the conference.
The Brussels conference was not meant to address the key sticking point of Assad's future role in the Geneva talks.
The rebels and their backers demand that Assad stand down but Moscow and Tehran show no sign of abandoning their long-time ally.
Assad's main backer Russia, which was also represented at the Brussels conference, said Tuesday's attack happened after an air strike hit a "terrorist warehouse" containing "toxic substances".
EU foreign affairs chief Federica Mogherini admitted it was "surreal especially today" to be discussing the "post-conflict situation".
"But if you want peace you have to start building peace and the conditions for peace," she said, urging a "strong push to the political talks in Geneva".
Delegates made clear that aid for reconstruction would not be forthcoming until there was a genuine political transition to a new Syrian government without Assad.
"Our publics will not accept that their money go in any way to those responsible for these crimes," Johnson said, referring to the Idlib attack.