Here’s How Rare Hearthstone Cards Actually Are

Here’s How Rare Hearthstone Cards Actually Are

When someone buys $50 (or more) worth of Hearthstone cards, they inevitably do some simple maths to figure out each card’s rarity. But those numbers aren’t actually useful for figuring out your chances of getting a legendary or golden card next time.

If you aren’t familiar with Hearthstone, it’s a collectible card game similar to Magic: The Gathering. To get more cards, you buy ‘expert packs’ with your in-game winnings, or with real money. You get random cards, with four levels of rarity — Common, Rare, Epic and Legendary.

The Wrong Numbers

So what’s the problem with everyone’s numbers? Each expert pack gives you five cards, one of which is guaranteed to be Rare or better. Let’s take my own post as an example:

Common 142 71.0%
Rare 49 24.5%
Epic 8 4.0%
Legendary 1 0.5%

So these numbers are accurate in that they reflect what percentage of each rarity we got in the 200 cards we drew, but they’re useless if I was trying to guess what future packs might hold and decide if it’s worth spending real money on expert packs. Every time you open a pack in Hearthstone, you’re getting five cards, so you need to find the probability that any of those five will be what you’re looking for, and account for the guaranteed rare card.

Data Sources

To find the data, I obviously couldn’t buy 1,000 packs, even on Kotaku‘s budget. But luckily, most people who plunk down $US50 (or more) on cards also tend to post their results for people to watch. So I manually entered data from a variety of videos into a spreadsheet. There was speculation that Blizzard changed the card drop rates since the game officially launched in March, so I only used videos that were posted within the past two months (91% from the past month).


OK, so now that we have more data, let’s see what useful information we can get out of it. We’re looking for something that can give us an idea of what will be in the next pack we open, and what that pack will be worth. So, from 1,000 packs:

Count Per cent of Total Probability Per Pack
Common 3565 71.30% 99.81%
Rare 1155 23.10% 73.11%
Epic 215 4.30% 19.73%
Legendary 65 1.30% 6.33%

So every pack you open has a 99.81% chance of containing at least one common card. Now we’re on the right track! If you go down from there, you’ll see that the chances of getting at least one legendary card in a pack are actually considerably better than the .5% that we got from our 40 pack experiment.

Now, while we did expand the sample size, we didn’t observe all the possible combinations of cards. In 1,000 packs, we saw 16 of 55 possible combinations. The most common pack after a ‘4100’ (4 common, 1 rare; 61% of packs) was a ‘3200’ (3 common, 2 rare; 12.20%).

Fun Facts

  • The chances of getting a pack with any 5 legendary cards is one in a million
  • The chances of getting a pack with any 5 golden legendary cards is 1 in 3.2 billion
  • There’s a 0.4% probability of getting 2 legendaries in a single pack
  • The probability of getting a pack with only one common card is about ~0.80%
  • There’s a 16.26% probability of getting a pack with any golden card
  • Only 2.19% of common cards were golden, while 7.69% of legendaries were
  • The average $US50 purchase of 40 packs will be worth about 3,600 Arcane Dust
  • The best pack in our sample was 1 common, 2 rares, 1 epic, and 1 legendary

Special thanks to @indiemaiden for crunching all the numbers, and Kotaku’s Chris Person for the image. If you’re interested in the videos where the data came from: 40 packs, 40, 15, 80, 40, 15, 40, 600, 90.


  • This is one reason why I prefer to keep to physical trading card games. Most of the time they’re semi-randomized, where if say you’re getting 8 cards in a pack, it’s guaranteed that one will be rare, 3 uncommon and 5 common. Some go beyond that and set up so that in a box of boosters there’s a fixed number of packs that will have something rarer than a standard rare card (a foil-stamped one or whatever). For example, Japanese TCG Weiss Schwarz has it set up so that there’s 8 cards per pack, 20 packs per box, 16 boxes per carton. Every box has 15 rares, 4 double-rares and 1 special rare. 2-3 boxes in the carton will have a foil-stamped special rare instead. It means that when you buy a pack, a box or a carton you always know exactly what number of each card rarity you’re going to get, so the results are strongly predictable (it also means that unless you’re hunting for specific stuff, 2-3 boxes is going to get you close to a full set of everything depending on the size of the set)

    In comparison, Hearthstone has a very low number of cards in a pack and have no idea what you’re going to get beyond the fact that one of them will be a rare. I guess the actual cost per pack is lower, but it’s also not a physical product.

    • And that’s why I prefer LCGs.

      You buy a pack and get a full playset of every card from that pack.

    • “I guess the actual cost per pack is lower, but it’s also not a physical product.”

      But you can also play online, which for some people makes it an improvement.

    • I don’t think I agree. If you take Magic, you’re talking about 1 guaranteed rare, 3 uncommons and the rest common, and you also get a fairly useless land card… but you’re also talking about a $6 pack not a $2 pack.
      Hearthstone only gives you 5 cards per pack not 15 but still guarantees a rare.

      Also you can’t disenchant your physical cards to create ones you actually want. That system offers a huge benefit over physical cards. I think the current hearthstone system could be better implemented because it’s a bit cumbersome and difficult to use right now, but it’s a great help.

  • Started playing Hearthstone. Have opened probably 6 or 7 packets. No legendaries to be seen. Two mates start playing. Open 3 packets each. Both have legendaries.

    Rage. SO MUCH RAGE.

  • Can someone explain this? Is the minus sign just a typo?

    “The probability of getting a pack with only one common card is about ~0.80%”

  • I thought that if you did well in arena your card packs had better cards in it? This is only valid for purchased cards?

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