Many of the victims were killed by falling trees but its feared the number could rise.
In New York City, 10 people have been killed and the public transport system remains closed until further notice.
As Sandy heads north for Canada, towns and cities along the east coast were counting the cost of the damage.
New York Mayor Michael Bloomberg said there was "no timeline" for when the city's subway would restart, but he hoped buses could begin running again today.
It is estimated Sandy will end up causing about £12.44 billion in property damage and £6.22bn to £18.66bn more in lost business.
The storm cut power to about seven million homes, shut down 70% of east coast oil refineries and inflicted worse-than-expected damage in the New York area.
New York City was all but closed off by car, train and air. The superstorm inundated the city's waterfront, flooded the financial district and subway tunnels and cut power to hundreds of thousands. Power is expected to be fully restored in Manhattan and Brooklyn within three days.
Most homeowners who suffered losses from flooding won't be able to claim on their insurance. Standard policies don't cover flood damage, and few homeowners have flood insurance.
In New York huge swathes of the city remained dark and nearly deserted.
Over 40 people were killed across seven states by the storm that made landfall in New Jersey.
The storm caused the worst damage in the 108-year history of the New York subway system, and there was no indication of when the network would be rolling again.
Water flooded tunnels, subway stations and the electrical system that powers Wall Street and sent hospital patients and tourists rushing for safety. Skyscrapers swayed and creaked in winds that partially toppled a crane 74 stories up. A large tanker ship ran aground on the city's Staten Island.
A fire raged in a city neighbourhood near the Atlantic Ocean, with 80 to 100 homes destroyed but no deaths reported.
The full extent of the damage in neighbouring New Jersey was revealed as morning arrived.
Governor Christie said seaside rail lines had been washed away; there was no safe place on the state's barrier islands. Parts of the coast were still under water.
"It is beyond anything I thought I'd ever see," he said. "It is a devastating sight."
The death toll from Sandy in the US included several killed by falling trees. Sandy also killed 69 people in the Caribbean before heading up the Eastern Seaboard.
Airlines cancelled more than 12,000 domestic and international flights. New York's three major airports remain closed.
President Obama declared a major disaster in New York and Long Island, making federal funding available to residents of the area. He also suspended campaigning for a third day.
"This was a devastating storm, maybe the worst that we have ever experienced," New York Mayor Michael Bloomberg said.