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What is a hash rate?

The hash rate (sometimes called the hash power) is the speed at which a mining device operates. To be successful at mining speed is of the essence since the miner is basically trying to solve a question (with a goal of solving the block) by trying lots of potential answers. The more answers suggested over the shortest period of time will increase the chances of solving that block.

The cryptographic hash function

A hash function in computer processing is a function that compresses information, meaning the output is generally shorter than the input. Hash functions are used in many parts of cryptography, to map data of differing sizes to data of a fixed size.

A cryptographic hash function is a type of hash function that has properties which make it suitable for use in cryptography (e.g. constructing something that prevents third parties accessing the information).

Cryptographic hash functions are ideal for processing cryptocurrency transactions. They are secure and are widely used in information security applications involving authentication, digital signatures and message authentication codes. In the context of cryptocurrency mining, a hash is one computation or “guess” at solving a block.

Laptop vs miner

Let’s try and put this into context. These days it’s impossible to mine Bitcoin using a standard desktop computer. The computational difficulty of mining is too high.

When Bitcoin first arrived it was possible to mine using a standard home computer or more specifically the computer’s GPU (graphics processing unit). A GPU is a part of the video rendering system of a computer and the work it does is very repetitive and deals with a high volume of information. Doing the same things to the pixels on the screen constantly to support video/graphics. This kind of bulky mathematical work can be done by a GPU much better and in a much higher volume than the computer’s CPU (central processing unit).

The hash rate of the laptop I’m using right now is 48 hashes per second. The hash rate of the highest specification bitcoin mining machine available to purchase on Amazon (the Bitmain New Antminer S9i) is 13,500,000,000,000 hashes per second.

Megahash, gigahash, terahash

That number is so big we need to talk megas, gigas and teras. These are the hash rates you will see being talked about in the context of cryptocurrency mining:

  • 1 kH/s* (one kilo hash) is 1,000 (one thousand) hashes per second
  • 1 MH/s (one mega hash) is 1,000,000 (one million) hashes per second
  • 1 GH/s (one giga hash) is 1,000,000,000 (one billion) hashes per second
  • 1 TH/s (one tera hash) is 1,000,000,000,000 (one trillion) hashes per second
  • 1 PH/s (one peta hash) is 1,000,000,000,000,000 (one quadrillion) hashes per second
  • 1 EH/s (one exa hash) is 1,000,000,000,000,000,000 (one quintillion) hashes per second
  •  1 ZH/s (one zeta hash) is 1,000,000,000,000,000,000,000 (one sextillion) hashes per second
  • 1 YH/s (one yotta hash) is 1,000,000,000,000,000,000,000,000 (one septillion) hashes per second

* kH/s is always written with a lower case k as upper case K is reserved for Kelvin (which is a measurement of heat).

Hash rate arms race

It isn’t hard to see that cryptocurrency mining is becoming progressively more difficult. In the case of Bitcoin deliberately so as the difficulty of mining is constantly adjusted to keep the production to a fixed time period. The more miners attracted to the mining effort then the more difficult it becomes. To be successful at mining requires more hash power to have any chance of sharing the rewards.

Let’s see how much effort is involved in mining one Bitcoin. Whilst you can’t mine one Bitcoin (the mining effort is used to solve a block that comes with a reward of 12.5 Bitcoins) we have treated it as though you can just to make the guide easier to follow.

This online calculator shows we need to deliver 16,500 TH/s per second for a whole day to mine one bitcoin (calculation made at 15/5/18 at 15.36). So if one Bitmain New Antminer S9i delivers 13.5 TH/s we would need 1,222 machines to mine one Bitcoin in a day.

Mining one Bitcoin with a laptop

For fun let’s see how long my laptop would take to mine one Bitcoin. From the example above we need to deliver a theoretical 16,500 TH/s for a whole day. We know my laptop has a hash rate of 48 so let’s do the maths. Brace yourself….

Theoretical TH/s for a day to mine one Bitcoin


TH per minute for a day to mine one Bitcoin


TH per hour for a day to mine one Bitcoin


TH per day to mine one Bitcoin


Total hashes


Computer hash rate per second


Total seconds required to deliver the required hashes


Total minutes required to deliver the required hashes


Total hours required to deliver the required hashes


Total days required to deliver the required hashes


Total years required to deliver the required hashes


That’s a long time. But a great illustration of how mining is now only viable with specific mining processors and joining a mining pool if you’re an individual. It also illustrates why professional mining operations in countries with access to lower power costs are contributing most of the mining effort.

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