<p>Each epoch is supposed to have about 21600 blocks per epoch, where an epoch is 5 days long. If every epoch had 21600 blocks, the density would be 100%. However blocks occasionally get skipped so the density will be less than 100%.</p>
<p>This is not the exact way that &quot;chain density&quot; is calculated (I forget the exact way it is calculated) but it should be enough to understand the concept.</p>

CC BY-SA 4.0
2022-07-28T02:30:09.627Z
2022-07-28T02:30:09.627Z
Erik de Castro Lopo
<p>Just building on top of answer from Erik, a simple way to look at it would be :
(number of blocks minted so far in current epoch) / (number of slots so far in current epoch)</p>
<p>In ideal scenario, the density should match the active slot co-efficient (0.05 on testnet and mainnet, i.e. on average - 5% of chances for a random slot to have a block minted).</p>
<p>Is there a risk to protocol if density is too low? While it's far from ideal / healthy, current consensus network should work fine as long as there is 1 block in stability window , viz : 3<em>k/f (i.e., 3</em>2160/0.05, which corresponds to ~ 1.5 days on testnet/mainnet).</p>

CC BY-SA 4.0
2022-07-28T05:56:58.400Z
2022-07-28T05:56:58.400Z
RdLrT
<p>What is block density? Pools currently before the Vasil upgrade are saying switch from 1.35.x back to 1.34.x to increase “block density”.</p>

CC BY-SA 4.0
2022-07-28T14:44:39.180Z
Bonus question, any idea why the current 1.35.x pre Vasil in testnet node seems to be dropping blocks, and reducing chain density?
TheStophe
CC BY-SA 4.0
2022-07-28T16:20:32.067Z
Looks like it’s an issue checking minFee between different era versions: https://github.com/input-output-hk/cardano-node/issues/4228#issuecomment-1195757220
TheStophe
<block-production><consensus>
What is block density?
# What is block density?

(Asked by: username_0 on 2022-07-28)

What is block density? Pools currently before the Vasil upgrade are saying switch from 1.35.x back to 1.34.x to increase “block density”.

**Tags:** block-production, consensus
> **Comments:**
> **username_0**: Bonus question, any idea why the current 1.35.x pre Vasil in testnet node seems to be dropping blocks, and reducing chain density?  
> **username_0**: Looks like it’s an issue checking minFee between different era versions: https://github.com/input-output-hk/cardano-node/issues/4228#issuecomment-1195757220  

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## 2 answers

### Answer by username_1 on 2022-07-28. Score: 2

Each epoch is supposed to have about 21600 blocks per epoch, where an epoch is 5 days long. If every epoch had 21600 blocks, the density would be 100%. However blocks occasionally get skipped so the density will be less than 100%.

This is not the exact way that "chain density" is calculated (I forget the exact way it is calculated) but it should be enough to understand the concept.


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### Answer by username_2 on 2022-07-28. Score: 2

Just building on top of answer from Erik, a simple way to look at it would be :
(number of blocks minted so far in current epoch) / (number of slots so far in current epoch)

In ideal scenario, the density should match the active slot co-efficient (0.05 on testnet and mainnet, i.e. on average - 5% of chances for a random slot to have a block minted).

Is there a risk to protocol if density is too low? While it's far from ideal / healthy, current consensus network should work fine as long as there is 1 block in stability window , viz : 3*k/f (i.e., 3*2160/0.05, which corresponds to ~ 1.5 days on testnet/mainnet).


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