US Secretary of State Hillary Clinton, co-hosting the conference with Mr Ban, offered $1.15bn.
The EU meanwhile pledged an additional $1.7bn for food and to support the rebuilding of Haitian President Rene Preval's government.
International aid will be used to build hospitals, schools and government buildings, create jobs, and reform Haiti's key farming sector.
Mr Ban said a "robust" internet-based tracking system run by the UN would be used to "ensure accountability and transparency" of the aid distribution.
Ban Ki-moon: "Our goal is not just to rebuild"
A commission co-chaired by President Preval and former US President Bill Clinton is supposed to ensure that the aid is well coordinated and well spent.
It is an attempt to let Haiti's government set the priorities for reconstruction while responding to donor concerns about its reputation for corruption, says the BBC's Barbara Plett at the United Nations.
Delegates repeatedly stressed that the only way to produce real and lasting results for Haitians was to strengthen and work with the government, not around it, as has been the case in the past, our correspondent adds.
The Haitian government and international officials have spent weeks putting together a plan for the country.
The first part of the plan is an 18-month project focusing on rebuilding destroyed infrastructure, government buildings, hospitals and schools - which is expected to cost almost $4bn.
Officials estimate that a total of $11.5bn in aid will be needed for long-term reconstruction, which will involve strengthening institutions and refocusing the economy.
Earlier in the conference, Mr Ban urged donor nations not to forget a separate appeal for $1.44bn for food aid and shelter launched by the UN last month. He said just half had so far been pledged.
Aid agencies have warned that thousands are vulnerable to April rains and the hurricane season in June.
The country was already the poorest country in the Western hemisphere before the 7.0-magnitude earthquake struck.
Unemployment and illiteracy were high among its nine million population, with about 80% living on less than $2 a day.
Both Haiti's government and donors are insisting that a strategy of decentralisation is at the heart of the reconstruction plan. They aim to increase development in parts of the country that are less vulnerable to natural disasters than the capital, Port-au-Prince.
The capital's population more than tripled to 2.5 million in the three decades before the quake.
Officials also hope to develop a rural agricultural strategy that would enable Haiti to become more self-sufficient. Haiti is dependent on food imports, yet about 80% of the population works in agriculture.
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