Ever since their cover of Katy Perry’s “ET” was first uploaded to YouTube in 2011, five college students have risen to the stage of international fame. In the past seven years alone, the a cappella group known as Pentatonix has won three Grammy Awards and has had nine of their albums appear in the top 10 of Billboard 200’s chart, many of which have achieved platinum certifications. Pentatonix mainly focuses on reworking hits of the pop genre or creating their own. However, all four of their incredibly popular holiday albums have also easily reached the top rankings of numerous Billboard charts. So, while you enjoy the spirit of the season or cram for finals, here are Pentatonix’s four holiday albums, ranked by popularity:

4. PTXmas (2012)

Pentatonix’s first Christmas album features six covers of timeless seasonal songs. The most notable track of the album is “Carol of the Bells”, gaining over 131 million views on YouTube. The group capitalized on the ability of the vocal harmonies, combining them together in a way that delivered the melodic tune perfectly, but also allowed for the ominous undertone that seems to be a recurring theme in all the album’s tracks. Avi Kaplan and Kevin Olusola, the bass singers at the time, intertwined light percussive elements with low baselines to provide a slightly brighter version of the typically hymnal classics, namely in “O Come, O Come Emmanuel”. PTXmas reached number 7 on Billboard 200’s charts, and while it didn’t quite near the level of complexity they have incorporated today, it provided a true insight into just how much the new a cappella group was capable of.

3. Christmas Is Here (2018)

As the most recent holiday album of the group, Christmas is Here! is only the second album to ever feature their newest member, bass singer Matt Sallee. Even though Kaplan, their former bass singer, decided to leave for a solo debut, Pentatonix still released twelve tracks that truly showcased the group’s growth. While again mainly composed of intricately reworked covers of popular holiday hits, this album did feature an original song, “What Christmas Means to Me”. In addition to their impressive lineup of songs, Pentatonix was able to produce a collaboration with Kelly Clarkson, in “Grown-Up Christmas List”. As 7th on Billboard 200’s charts, Christmas is Here! showcased the group’s clear progress in discovering their musical style, with both bright, lighthearted tunes and solemn carols characterizing the 2018 edition of the Pentatonix holiday release.

2. That’s Christmas to Me (2014)

The second experiment in holiday cheer was marked by a developing transition to more modern Christmas hits. With the debut of their first original Christmas song, “That’s Christmas to Me”, Pentatonix combined the typical elements of holiday anthems with their own personal flair. A collaboration with widely known artist Tori Kelly, “Winter Wonderland/Don’t Worry Be Happy”, helped propel them to the international spotlight. Throughout the album, melodies sung by Mitch Grassi, Scott Hoying, and Kirstin Maldonado sharply contrasts the darker tones of their friends to recreate the songs that are still sung every holiday season, with their signature style of innovative a cappella effects. The album reached the 2nd spot on Billboard 200’s chart, making it a highlight of their 2014.

1. A Pentatonix Christmas (2016)

Pentatonix’s most successful holiday album did not disappoint. When released, the commendable eleven tracks are possibly their best seasonal work yet, featuring two original songs, “The Christmas Sing-Along” and “Good to Be Bad”. Every last drop of talent had been poured into each ingeniously crafted track, with multiple layers of new, unexplored voice textures and passion unheard of yet. This album truly tested the limits of a human voice, including numerous effects that added to the overall fast rhythm of some song, namely upbeat hits like “Up on the Housetop”. Again, Pentatonix’s consistent vocal talents were showcased with some classic, lyrical Christmas songs, such as “O Come All Ye Faithful”. Their first number one album on Billboard 200’s chart has sold over 1,000,000 copies since its 2016 release, formally establishing their prominence in the music industry.