Hashrate Demystified: From H/s to EH/s

What Even Is a Hash?

Before we talk about hashrate, let’s nail down what a “hash” is — because this single concept underpins everything in Bitcoin mining.

A hash is the output of a one-way mathematical function. You feed it some data — any data, from a single letter to an entire movie — and it spits out a fixed-length string of characters that looks like complete gibberish. Here’s the key part: you can’t reverse the process. Given the output, there’s no way to figure out what the input was, short of trying every possibility.

Think of it like a meat grinder. You can put a steak in and get ground beef out. But you absolutely cannot reconstruct the original steak from the ground beef. That’s a one-way function.

Bitcoin uses a specific hash function called SHA-256 (Secure Hash Algorithm, 256-bit). No matter what you feed into SHA-256, you always get a 256-bit number out — typically displayed as 64 hexadecimal characters. Change even a single comma in the input, and the output is completely, unpredictably different.

Tip

You can try SHA-256 yourself online. Hash the word “bitcoin” and you’ll get one result. Hash “Bitcoin” (capital B) and the result is entirely different. This unpredictability is what makes mining work.

So What Is Hashrate?

Hashrate is simply how many of these hash calculations your mining hardware can perform per second. That’s it. If your miner does 100 trillion hashes per second, your hashrate is 100 TH/s (terahashes per second).

Why does speed matter? Because Bitcoin mining is essentially a massive guessing game. Your miner is trying to find a hash output that meets a certain condition (more on that in the difficulty article). Every hash is a guess. The more guesses you can make per second, the better your chances of finding the winning answer.

The Lottery Ticket Analogy

Imagine a lottery where a winning ticket is drawn every 10 minutes. You can buy as many tickets as you want — millions, billions, trillions of them. Each hash your miner computes is like buying one lottery ticket.

• A miner doing 1 TH/s is buying 1 trillion tickets per second.
• A miner doing 200 TH/s is buying 200 trillion tickets per second.
• The miner with 200 TH/s has 200 times better odds of winning any given draw.

Your hashrate is your ticket-buying speed. More hashrate = more tickets = better odds.

The Unit Prefixes: K, M, G, T, P, E

Hashrate numbers get astronomically large, so we use standard metric prefixes to keep things readable. Here’s the full table:

Unit	Symbol	Hashes per Second	Power of 10
Hash	H/s	1	10^0
Kilohash	KH/s	1,000	10^3
Megahash	MH/s	1,000,000	10^6
Gigahash	GH/s	1,000,000,000	10^9
Terahash	TH/s	1,000,000,000,000	10^12
Petahash	PH/s	1,000,000,000,000,000	10^15
Exahash	EH/s	1,000,000,000,000,000,000	10^18

Each step up is 1,000 times the previous one. So 1 TH/s = 1,000 GH/s = 1,000,000 MH/s.

Note

In the early days of Bitcoin (2009-2010), people mined with CPUs at a few MH/s. Today, a single modern ASIC miner like the Antminer S21 does around 200 TH/s. The entire Bitcoin network hashrate is measured in hundreds of EH/s. That’s how far we’ve come.

Which Units Matter Today?

• TH/s — This is what individual ASIC miners are rated in. When you’re shopping for a miner, you’ll compare them in TH/s (or sometimes just “T”).
• PH/s — Small-to-medium mining farms measure their total capacity in PH/s.
• EH/s — The total Bitcoin network hashrate is discussed in EH/s. As of recent times, the network hovers around 600-800+ EH/s.

You’ll rarely see KH/s or MH/s in Bitcoin mining conversations anymore. Those units are more relevant for mining other cryptocurrencies with different algorithms.

Hashrate and the Probability of Finding a Block

Here’s where it gets real. Your share of the total network hashrate directly determines your probability of mining the next block.

The math is simple:

Your probability = Your hashrate / Total network hashrate

Let’s run some numbers. Say you have a single miner doing 200 TH/s, and the network hashrate is 600 EH/s:

200 TH/s = 0.0002 EH/s
0.0002 / 600 = 0.000000333 = 0.0000333%

That’s a roughly 1-in-3,000,000 chance of finding any given block. Since blocks are found roughly every 10 minutes (144 per day), you’d statistically find one block every:

3,000,000 / 144 = ~20,833 days = ~57 years

Yeah. That’s why solo mining with a single machine is essentially playing the longest lottery ever. But the math scales linearly — if you have 1,000 of those miners (200 PH/s total), your expected time drops to about 21 days.

Caution

These are statistical averages. You could find a block on your first day, or you could go twice as long as the average. Probability doesn’t guarantee anything — it just tells you what to expect over long periods.

Hashrate vs. Revenue

More hashrate means more potential revenue, but it’s not the only factor. Your actual mining income depends on:

1. Your hashrate — More is better, obviously.
2. Network hashrate — If the total network hashrate doubles but yours stays the same, your share of rewards gets cut in half.
3. Bitcoin price — You earn BTC, but pay bills in fiat. Price matters.
4. Block reward — Currently 3.125 BTC per block (after the April 2024 halving).
5. Transaction fees — These vary and add to the block reward.
6. Electricity cost — The biggest operational expense. A more efficient miner (more TH/s per watt) earns the same while spending less on power.

This is why you’ll often see miners talk about efficiency in terms of J/TH (joules per terahash) or W/TH (watts per terahash). A miner that does 200 TH/s at 3,500W (17.5 W/TH) is far more profitable than one doing 200 TH/s at 5,000W (25 W/TH) — same hashrate, but the second one eats 43% more electricity.

Network Hashrate: The Big Picture

The Bitcoin network hashrate is the combined hashing power of every miner on the planet. It’s a measure of how much computational work is being thrown at Bitcoin mining at any given moment.

When you see headlines like “Bitcoin hashrate hits new all-time high,” it means more mining hardware is online than ever before. This generally indicates:

• More miners are competing — making it harder for each individual miner.
• The network is more secure — it would cost more to attack.
• Difficulty will likely increase — the protocol adjusts to maintain ~10 minute block times.

Network hashrate is not directly measured — it’s estimated based on how quickly blocks are being found relative to the current difficulty. If blocks are coming in faster than every 10 minutes, the estimated hashrate is higher than what the current difficulty was calibrated for.

Your Hashrate: What You Control

When you look at your mining dashboard, you’ll typically see several hashrate figures:

• Real-time (instantaneous) hashrate — This fluctuates wildly. It’s based on how many shares you’ve submitted in the last few minutes. Don’t panic if it bounces around.
• Average hashrate (15m, 1h, 24h) — These are smoothed averages. The 24-hour average is the most reliable indicator of your actual performance.
• Nominal (rated) hashrate — What the manufacturer says the miner should do. Your actual hashrate should be close to this, but environmental factors (temperature, power supply quality) can cause variation.

Tip

If your 24-hour average hashrate is consistently more than 5% below the rated hashrate, something might be wrong. Check your power supply, cooling, and network connection. Overheating is the most common culprit — miners automatically throttle (reduce speed) when they get too hot.

Hashrate in Practice: Choosing a Miner

When comparing miners, hashrate is just one dimension. Here’s a quick mental framework:

What to Compare	Why It Matters
Hashrate (TH/s)	Raw mining power
Power consumption (W)	Your electricity bill
Efficiency (J/TH)	Profitability per unit of power
Price ($)	How long until you break even
Noise (dB)	Can you live near it?

A miner with twice the hashrate but three times the power consumption is actually less profitable per watt. Always think in terms of efficiency, not just raw speed.

Quick Recap

• A hash is the output of a one-way function. SHA-256 is the one Bitcoin uses.
• Hashrate is how many hashes per second your hardware can compute.
• Units go from H/s up through KH/s, MH/s, GH/s, TH/s (individual miners), PH/s (farms), and EH/s (network).
• Your probability of finding a block equals your hashrate divided by the total network hashrate.
• More hashrate means better odds, but efficiency (J/TH) determines actual profitability.
• Network hashrate reflects total global mining competition and directly impacts your earnings share.

Now that you understand hashrate, the next article explains difficulty — the mechanism Bitcoin uses to keep blocks coming every 10 minutes no matter how much hashrate the network has.