Eighteen-year-old Charlotte Johnson, left, who studies at Harlow College, took part in Go Sober for October and remained teetotal throughout the 31 days.
The aspiring music journalist asked family and friends to sponsor her the price of a pint of beer or glass of wine from a pub with proceeds going to Macmillan Cancer Support.
“Being the only sober person in my friendship group really tested my willpower,” she told the Hertfordshire Mercury.
“But remembering the reason behind the fundraiser, I stayed motivated and determined to complete the challenge.”
Charlotte’s online page and her collections from The Fox and Duck and the Jolly Sailors pubs in Hertfordshire raised a total of £83.35.