<p>To look at it a different way, the probability for solving a block in Bitcoin is approximately:</p>

<pre><code>1 / ({total network hash per second} x {average block time in seconds})
</code></pre>

<p>Note that block time is the average.</p>

<p>As of writing, this is:</p>

<pre><code>Probability = 1 / (24,667,167,000,000,000 x 600)
= 1 / 1.48003002×10¹⁹
= 6.75661970694351186200939356621969059789746697164966964... × 10^-20 (WolframAlpha)
</code></pre>

<p>Data source: <a href="https://blockchain.info/charts/hash-rate" rel="nofollow noreferrer">blockchain.info</a></p>

CC BY-SA 4.0
2018-08-06T22:34:27.033Z
That '0' doesn't look very accurate or useful.
Pieter Wuille
CC BY-SA 4.0
2018-08-07T09:16:24.483Z
@PieterWuille You are right, I didn't try very hard for that. I will improve it.
Willtech
CC BY-SA 4.0
2018-03-02T10:15:03.633Z
2018-08-07T09:22:24.270Z
2018-08-07T09:22:24.270Z
Willtech
<p>I've been using cryptocurrency revenue calculators and have appeared to figure out that for all of the major algorithms, the probability of a hash being valid is 1/(D*2^u) where u is either 0, 13 (weird), or 32 and D is the network difficulty. I used the formula (my_hashrate<em>block_reward</em>time) * 1/D * 1/2^u to find revenue. I believe the following is true:</p>

<p>u = 32 for SHA-256, Scrypt, X11, Groestl, X11Ghost, Lyra2Rev2, NeoScrypt, Blake (14r)<br>
u = 13 for Equihash<br>
u = 0 for CryptoNight, Ethash<br></p>

<p>Can someone explain this phenomenon? Will the constant part of the probability change over time or will the difficulty adjust?</p>

<mining-profitability><difficulty>
Probability of Finding a Block
John
# Probability of Finding a Block

(Asked by: username_0 on 2018-03-01)

I've been using cryptocurrency revenue calculators and have appeared to figure out that for all of the major algorithms, the probability of a hash being valid is 1/(D\*2^u) where u is either 0, 13 (weird), or 32 and D is the network difficulty. I used the formula (my\_hashrate*block\_reward*time) \* 1/D \* 1/2^u to find revenue. I believe the following is true:

u = 32 for SHA-256, Scrypt, X11, Groestl, X11Ghost, Lyra2Rev2, NeoScrypt, Blake (14r)  
u = 13 for Equihash  
u = 0 for CryptoNight, Ethash

Can someone explain this phenomenon? Will the constant part of the probability change over time or will the difficulty adjust?

**Tags:** mining-profitability, difficulty


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## 1 answers

### Answer by username_1 on 2018-03-02. Score: -1

To look at it a different way, the probability for solving a block in Bitcoin is approximately:
1 / ({total network hash per second} x {average block time in seconds})

Note that block time is the average.
As of writing, this is:
Probability = 1 / (24,667,167,000,000,000 x 600)
= 1 / 1.48003002×10¹⁹
= 6.75661970694351186200939356621969059789746697164966964... × 10^-20 (WolframAlpha)

Data source: blockchain.info

> **Comments:**
> **username_2**: That '0' doesn't look very accurate or useful.  
> **username_1**: @PieterWuille You are right, I didn't try very hard for that. I will improve it.  

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