Why does SHA256 miner hash have to be lower than the current target 256bit hex?

Question

I'd like to ask if someone can help explain this definition found on https://en.bitcoin.it/wiki/Target

"The SHA-256 hash of a block's header must be lower than or equal to the current target for the block to be accepted by the network". I understand that target means difficulty. But I don't understand what the hash being lower than the target actually means.

I looked on youtube for explanations of target hash but they returned an investopedia definition.

Thank you in advance.

Does this answer your question? How often does target hash change and how to find it?. The hash is a number. Just like 33 is a number. The target is a number. Just like 76 is a number. We can see that a hash is less than a target just like we can see 33 is less than 76. if hash < target { publish_block() } else { nonce++; continue loop } — RedGrittyBrick, Apr 14 '22 at 09:49

Bitcoin_1o1 · Answer 1 · 2022-04-14T01:53:17.737

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Target and Difficulty are separate concepts. You may want to take a look at this answer I wrote for another question: How often does target hash change and how to find it?

edited Apr 14 '22 at 01:53

answered Apr 14 '22 at 00:40

Bitcoin_1o1

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Rick Park · Answer 2 · 2022-05-14T14:02:14.827

There are no magic math to understand for this: simply it was needed some target to let people calculate and mine with some difficulty having success after a certain time. The “lower than” has been chosen, but “greater than” some number or “comprised between “ a couple of number works in the same way. The “lower than” has the useful property that declaring a single parameter (the threshold) you tune all the miner on the target (i.e. 0 < x < threshold) and that as lower is the parameter as higher is the number of guess you should test before to find a good one. You need to define some interval because it is practically impossible to find a single number which when passed trough sha256 yields a certain target number value exactly.

Why does SHA256 miner hash have to be lower than the current target 256bit hex?

2 Answers2