The news was greeted with spontaneous applause among some of about 65,000 people who were evacuated to enable experts to make the bomb safe, BBC reported on Sunday.
Many residents are now awaiting permission to return to their homes.
The evacuation on Sunday morning was the biggest in post-war German history, involving hundreds of officials. Police checked every designated house with heat-detection technology to make sure everyone was out.
The evacuation area in the Westend district included hospitals, nursing homes and Germany’s central bank. There are believed to be hundreds of thousands of unexploded wartime bombs across Germany.
Police early on Sunday morning cordoned off the 1.5 km evacuation area as residents carrying luggage vacated the danger zone. A few stragglers who were slow to move may be prosecuted, local media reported.
Many residents made the most of the day, either by visiting relatives or enjoying a day out in a different part of the city.
Police told local media that the evacuation took place on schedule even though a handful of residents – for various reasons – were not initially prepared to vacate the area.
The 1.4 tonne British bomb was found on a building site last Wednesday.
More than 100 patients from two hospitals were moved on Saturday including premature babies and people in intensive care. Some care home residents left early on Sunday.
Fire and police chiefs in the city warned that an uncontrolled explosion of the HC 4000 bomb would be powerful enough to flatten an entire street.
The bomb disposal operation was completed ahead of the 12-hour estimate.
Police helicopters carrying heat detecting cameras scoured the area as bomb disposal experts began their task. Police will continue guarding empty houses and apartments from burglars until evacuees have returned home.
The area affected included 20 retirement homes, an opera house, and Germany’s central bank where half the country’s gold reserves are stored.
The city opened shelters for evacuees to spend the day, and most museums opened their doors for free.
A smaller evacuation took place on Saturday in Koblenz, about 110 km west of Frankfurt, while experts disposed of a World War II that had been found during the construction of a new kindergarten.