Players are constantly asking what DLC to purchase. This guide provides a quick overview to the types of DLCs, so you can make an informed choice.

Up to the present, Paradox (the publisher) has made DLCs available at 50-75% off during various Steam sales each year. The cheapest way to get the "entire" game is to wait for such a sale and "stock up" on anything you lack. It is rare for the very latest DLCs to be on sale, so if you want to be totally up-to-date, expect to pay full price for some of the most recent releases.

This guide is updated through March, 2017

Game Length Adjustments:
The standard game starts in 1066, ends in 1453 AD. These expansions allow earlier starts:
- THE OLD GODS (allows 867 AD start, including "bookmark" scenarios)
- CHARLEMAGNE (allows 769 AD start, including "bookmark" scenarios)
- CK2 to EU4 CONVERTER (allows you to import CKII game result as EUIV start)

Game System Depth:
Additional rules that add a larger variety of more complicated decisions:
- WAY OF LIFE (gives more control and variety to decision-making, but with interesting limits)
- CONCLAVE (forces you to deal with politics within your realm, adds challenge & complexity)
- RULER DESIGNER (design your own starting ruler, but disables achievements)

Additional Culture/Government/Religion Types:
Adds variety and depth by letting you play something other than a Feudal Western European.
- LEGACY OF ROME (Retinue system & Byzantine Imperial system)
- SWORD OF ISLAM (Islamic Iqta' system)
- HORSE LORDS (Steppe nomads of Central Asia)
- RAJAS OF INDIA (Indian subcontinent, with multiple new religions)
- SONS OF ABRAHAM (playable Jews, some additional religious options)
- THE REPUBLIC (Merchant city republics like Venice or the Hanseatic League)

Historical Challenges:
- THE REAPER'S DUE (disease, plagues, medieval "medicine" and "doctors," hospitals)
- SUNSET INVASION (ahistorical invaders from the Americas, for "balance")
- MONKS & MYSTICS (councillor expansion, four secret societies for various religions)

For additional insights, see http://www.ckiiwiki.com/Downloadable_content

These don't add to gameplay, but provide a much richer visual experience to the illustrations in the character dialog windows and the character icons on the map.

- DYNASTY SHIELDS (greater variety of heraldry, great for fans of the subject)
- FACES / PORTRAITS / CLOTHING (additional faces & headgear for various regions)
- UNIT & BOAT PACKS (additional land and sea military units on the map)
- COUNCILLORS PACKS (additional dress for councillors on the map)
- CUSTOMIZATION PACK (can customize names, titles, coats of arms, and your portrait)

For a complete list of each category, see http://www.ckiiwiki.com/Graphical_DLC

The orchestral background music is quite rich and well done. There are two general categories of additional music:

- SONGS OF ... (adds more variety to the orchestral background music)
- ... METAL (adds "metal" genre background music)

Some pieces become part of the standard musical background rotation, while others only appear when playing as a specific culture. One DLC only plays during the Christmas season! For complete details about each, see http://www.ckiiwiki.com/Music#DLC

THE OLD GODS and CHARLEMAGNE amost double the gameplay options by extending the game's time period by 200 or 300 years. They probably represent the best value in DLC, provided you enjoy the gameplay. The CK2 to EU4 converter was updated considerably in late 2016, but can still yield odd results, since CK2 can drift dramatically from actual history.

WAY OF LIFE is generally liked, but CONCLAVE introduces political complexities and limitations that were especially frustrating to "old guard" players. The RULER DESIGNER currently disables all game achievements. It is only recommended to players no longer interested in earning Steam achievements.

The additional cultures/governments/religions provides new challenges once you've mastered the western Europeans. LEGACY OF ROME seems the most popular, but SWORD OF ISLAM provides a fascinating chance to be the "great opponent" of Christian Western Europe. HORSE LORDS and RAJAS OF INDIA expand map and gameplay possibilities further east. Nomads are considered especially powerful by some. SONS OF ABRAHAM and THE REPUBLIC provide the least additional value. However, min-max players often recommend being (or becoming) a REPUBLIC for maximizing your wealth, while SONS OF ABRAHAM makes Judaism a playable religion and adds some additional religious details (mostly to Christianity, a few to Islam).

REAPER'S DUE adds a key element of medieval history, but some players dislike random diseases or plagues interfering with their orderly conquest of Eurasia, or perhaps wiping them out entirely! Enjoying this expansion requires a flexible mindset. SUNSET INVASION tries to create a "Mongols from the West" with an extremely far-fetched ahistorical scenario. Almost nobody uses it regularly, most consider it an extremely optional purchase. MONKS & MYSTICS is not yet available at the time of this writing.

The GRAPHICAL EXPANSIONS add considerable visual panache. The different faces and troop types also make differences more recognizable, and culture mixtures more fascinating as they evolve. The historical outfits and portrayals are fairly up-to-date with current historical scholarship (unlike the game map, which has some oddities).

The MUSIC EXPANSIONS are purely a matter of personal taste. For those who regularly enjoy games playing background music from the game developers, these are a "must." The music is nicely integrated into the random background rotation, and respects certain in-game variables, such as the player's culture, or their current "piety" level (higher piety means more religious-themed music). However, for everyone else, this is probably quite optional.