Difficulties calculating mined ETH per month

Question

I am trying to replicate calculator for ethereum mining available at

https://www.cryptocompare.com/mining/calculator/eth

So far I got to following formula

Seconds in 1 month / (Total Hash Power MH/s / My Hash Power MH/s * Block Time s) So in my case with following parameters:

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Seconds per month: 2592000

Total Hash power MH/s: 30728202.35

My hash power MH/s: 74.525

Block Time s: 15

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I get 0.4190912262 as a result opposed to 2.10 value from online calculator mentioned above. I'm not entirely sure where my formula is wrong i.e. I calculate seconds needed to mine 1 block and then divide whole month by these seconds to find out how many blocks I can mine.

For simplicity assume all other costs like electricity etc.. are 0

Answer 1

Let

A = blocksPerMonth
  = nSecondsPerMonth / blockTime
  = 2592000 / 15
  = 172800

B = chanceOfWinning
  = yourHashPower / totalHashPower
  = 74.525 / 30728202.35
  = 0.00000242529644758083

The chance of winning a single block is then:

A * B = chanceOfWinningOneBlock
      = 172800 * 0.00000242529644758083
      = 0.419091226141968

This is the number you calculated. You simply have to multiply that by 5 (which is the number of ether one wins if one wins the block) to get the number you're looking for.

(A * B) * 5 = expectedEtherPerMonth
            = 0.419091226141968 * 5
            = 2.09545613070984