Whole Again - Chart Performance

Chart Performance

The single debuted at number one in the United Kingdom with first week sales of 69,286 copies, and since gone on to sell 962,494 copies in the UK alone. It stayed atop the UK Singles Chart for four weeks, becoming the longest-charting number one since Westlife at Christmas 1999, and the only single which increased on weekly sales during each week at number 1. It is the fourth best-selling single by a girl group of all time, after "Wannabe" and "2 Become 1" by the Spice Girls, and "Never Ever" by All Saints, as well as being the best-selling girl group single of the decade. It also became the thirteenth overall best-selling single of the decade.

In Australia, it peaked at number two in the charts, being certified double platinum for sales of over 140,000 copies. The single was also released in Germany and New Zealand, where it secured a number one position for six consecutive weeks on both countries. In Germany, the single was certified platinum, one of three singles by a girl group to ever be certified Platinum; the others being "Daylight in Your Eyes" by No Angels and Shame by Monrose. The single was certified double platinum in New Zealand, one of the best selling singles by a girl group of all time there. The song achieved the most success in the UK, Germany, New Zealand, Austria, the Netherlands, Ireland, Turkey, Singapore and South Africa.