Around 145 million cards are sent from admirers and spouses - with 25 million sent in the UK.
But, the history behind this date is actually quite grisly, involving Saint Valentine, in 269 AD.
Here is what we know about Saint Valentine and why we celebrate his life on 14 February.
Who was Saint Valentine?
Valentine was a priest or bishop in Rome, who lived during the third century after Christ.
He was allegedly jailed by Roman emperor Claudius II for his deceit and unwillingness to obey the emperor's orders to stop performing Christian marriages.
He was also said to be guilty of helping persecuted Christians.
Claudius had ruled against Christian teaching as he did not want people to worship anyone other than him.
According to legend, Saint Valentine wrote letters to Claudius’ daughter, and miraculously rid her of blindness.
He also befriended Claudius, but when he tried to convert the emperor to Christianity, he was condemned to death.
Valentine wrote his final letter to the daughter of Claudius before his execution, signing it “from your valentine”.
He was beaten with clubs and stones, then beheaded outside the Flaminian Gate in Rome before being buried at a Christian cemetery on the Via Flaminia.
Saint Valentine is not thought to have had any intimate relationship with Claudius’ daughter.
Why did he become a saint?
Saint Valentine was given a feast day by Pope Gelasius in 496 AD, in celebration of the Christian martyr.T
The Feast of Saint Valentine (Saint Valentine's Day) has been observed each 14 February since then.
In the high middle ages (1000-1250 AD), Saint Valentine became an icon for love and romance.
However, the saint's name was removed from the General Roman Calendar in 1969 as there is little history around his acts and many speculate that the story of Saint Valentine has been skewed by various other versions.
This includes a French 14th-century manuscript illustration of Valentine overseeing the building of his basilica in Terni, Italy. This depicts him as a bishop in Terni, whereas the original story refers to him as a Roman priest.
He is still identified as a saint by the Catholic church, and his feast day celebrates his life on the day he was killed - 14 February.
What is Saint Valentine the patron saint of?
Saint Valentine is the patron saint of lovers, epileptics, and beekeepers.
How is his life celebrated on Valentine’s Day?
The story that he signed his final letter “from your Valentine” has led to the tradition of sending and receiving anonymous cards, letters and poems from admirers.
Celebrations began in the middle ages in England and France, with English poet Geoffrey Chaucer celebrating Saint Valentine in his 1375 poem “Parliament of Foules.”
He wrote: “For this was sent on Seynt Valentyne’s day / Whan every foul cometh ther to choose his mate.”
Today, people in the UK spend on average of £23 per person, a total of £926 million.
Around 75 percent of adults in the UK will celebrate Valentine’s Day, with millenials spending the most - approximately £32 per head.
According to Finder.co.uk, around a quarter of couples not living together will break lockdown to see their partner this year, while others plan Zoom nights and look forward to being reunited later in the year.