Norwegian Foreign Minister Borge Brende offered the figure at the end of Sunday's one-day conference, far beyond the $4 billion initially sought by Palestinian President Mahmoud Abbas.
"The message was clear to the international community that the Palestinian brothers are not alone," Egyptian Foreign Minister Sameh Shukri said.
The pledges followed US Secretary of State John Kerry earlier announcing immediate American assistance of $212 million. The European Union pledged 450 million euros ($568 million), while Turkey, which has been playing a growing role in the Middle East in recent years, said it was donating $200 million.
Delegates representing some 50 nations and 20 regional and international organizations applauded the pledge by Qatar, a tiny but energy-rich Gulf Arab nation at odds with its larger neighbors, like the Emirates.
The Emirates, like regional heavyweight Saudi Arabia, alleges that Qatar uses its massive wealth to undermine regional stability, primarily through meddling in other nations' affairs and aiding militant Islamic groups like Gaza's Hamas and the Muslim Brotherhood, the Arab world's oldest Islamist group with branches across much of the region.
Qatari Foreign Minister Khalid bin Mohammed al-Attiyah, in announcing his country's pledge, denounced the "international silence" that surrounded Gaza's destruction.
"While the Palestinian people need financial support, they need more political support from the international community," he said. "A just peace is the only real guarantee for not destroying what we are about to rebuild and reconstruct."
Organizers of the Cairo conference hope the pledges will be paid over the period of three years to aid reconstruction in the Gaza Strip, which borders Israel and Egypt. Both countries have blockaded Gaza since Hamas took power there in 2007, causing the territory of 1.8 million people economic hardships and high unemployment.
Donors plan to funnel the aid through Abbas' Palestinian Authority, and bypass Hamas. Abbas and Hamas recently formed a national unity government which held its first Cabinet meeting in Gaza last week.
The Western-backed Abbas, speaking to delegates, said the latest Gaza war caused "tragedies that are difficult to be described by word... Entire neighborhoods have been reduced to rubble." The 50-day war was the third between Hamas and Israel since 2008.
"The (Palestinian) government will carry out the reconstruction plan with full responsibility and transparency in coordination with the UN, the donors, international financial institutions, civil society and the private sector," he said.
Leading participants said the reconstruction of Gaza cannot be carried out in isolation from efforts to revive Israeli-Palestinian talks in search of a comprehensive and lasting settlement and.
"We must not lose sight of the root causes of the recent hostilities: A restrictive occupation that has lasted almost half a century, the continued denial of Palestinian rights and the lack of tangible progress in peace negotiations," said UN Secretary-General Ban Ki-moon, who later announced in a news conference that he planned to visit Gaza on Tuesday.
"I call on all parties to come together to chart a clear course toward a just and final peace," Ban said. "Going back to the status quo is not an option; this is the moment for transformational change."
The latest conflict in Gaza was the most ruinous of the three wars, killing more than 2,000 Palestinians – mostly civilians, the UN says. Another 11,000 were wounded, and some 100,000 people remain homeless.
Kerry said Gazans "need our help desperately – not tomorrow, not next week, but they need it now." He said the new US money, which nearly doubles American aid to the Palestinians this year, would go to security, economic development, food and medicine, shelter and water and sanitation projects.
Egyptian President Abdel-Fattah al-Sisi, whose government negotiated the cease-fire that ended the most recent war, said the reconstruction effort hinged on a "permanent calm" between Hamas and Israel, and required the exercise of "full authority" by the Palestinian Authority led by Abbas.
Egypt has had tense relations with Gaza's Hamas rulers since the Egyptian military ousted Islamist President Mohammed Morsi in July last year and threw its weight behind the administration of Abbas in the West Bank. Morsi belonged to the Muslim Brotherhood and his overthrow strained ties between Egypt and Qatar.
Al-Sisi said the conference sent a message that "the status quo must not continue, cannot be returned to, and that any attempt to bring about temporary stability will not last long."
"I tell the Israelis, both citizens and government: The time has come to end the conflict without further delay, to grant rights and establish justice so that prosperity and security can prevail," he said.
Palestinian-Israeli peace talks have broken down, and Abbas used the conference to warn that the failure to reach a deal posed a serious threat to regional stability.
"Israel's aggression on the Gaza Strip exposed the fragility and dangerous nature of the situation in our region in the absence of a just peace," Abbas said. He called on the international community to support his bid to get the UN Security Council to dictate the ground rules for any future talks with Israel, including by setting a deadline for an Israeli withdrawal from Palestinian lands.
EU negotiator Catherine Ashton appeared to back the arguments of Ban, Abbas, al-Sisi that work must begin to reach a comprehensive settlement for the Palestinian-Israeli conflict.
"I want to stress one more time that the solution for Gaza cannot be found in Gaza alone," she said. "Only a credible resumption of the peace negotiations can allow for a durable solution to the current crisis.
"This must be the last time in which the international community is called upon to rebuild Gaza. There cannot be a return to the status quo which has proved unsustainable," she added.