Bitcoin was the first digital asset whose issuance is entirely governed by a predetermined algorithm. Its operation rests on three core factors that regulate the release of new coins: overall hash rate, halving events, and the network difficulty parameter.
What “network difficulty” means in Bitcoin
Bitcoin’s network difficulty is a metric showing how much computational resource miners need to find the next block and add it to the blockchain. You’ll also see it called “mining difficulty.”
The unit of measure is hashes per second; for convenience, prefixes like K, M, G, T, etc. are used.
Difficulty is characteristic of networks that use the Proof-of-Work (PoW) consensus mechanism, as in Bitcoin and a number of other projects. Networks that have moved to Proof-of-Stake (PoS) do not have this metric.
When miners’ combined computing power grows, difficulty rises; when hash rate falls, difficulty decreases. Thanks to this feedback loop, blocks are produced at a roughly constant interval of about 10 minutes, and issuance remains predictable.
The protocol regularly recalculates difficulty to maintain a steady issuance pace within each cycle.
Why PoW keeps the blockchain “running on computation”
Proof-of-Work is the first widely adopted consensus mechanism, implemented in Bitcoin. The idea is straightforward: to inсlude a new block in the chain, a miner must find a hash that meets a set threshold (for example, starting with a certain number of leading zeros). Each additional zero makes the task exponentially harder and demands more energy and power. This “work” secures the network: rewriting transaction history is practically impossible because it would require re-hashing the entire chain at enormous cumulative difficulty.
The flip side of PoW is high energy consumption. The computations exist solely for network security and do not provide any other societal utility. As more miners join, the puzzles become harder and energy usage climbs—even though the average block interval (about 10 minutes in Bitcoin) stays the same. This trade-off spurred the search for alternatives such as Proof-of-Stake.
How difficulty affects issuance
A rising hash rate speeds up block discovery—temporarily increasing coin issuance. A drop in total power slows block production and reduces the issuance rate.
To smooth these swings, the protocol recalculates difficulty every 2,016 blocks (roughly every two weeks). If the actual block time deviates from the 10-minute target, difficulty is adjusted. This mechanism keeps issuance within predictable bounds and supports the planned deflationary model.
Current difficulty levels and trends
In September 2025, Bitcoin’s difficulty exceeded 130 T—an all-time high. Since the start of 2025 it has risen by about 16%, and over the last five years it has grown more than sixfold, reflecting the expansion of the mining industry and rising interest in the asset.
For comparison: in early 2017 difficulty was below 500 G—about 250 times lower than today. In the early years (up to 2010 it stayed under 1 K), mining was feasible on standard desktop CPUs.
As participation and network complexity increased, CPUs became insufficient. In 2013, specialized ASIC devices appeared, vastly outperforming CPUs. This triggered a sharp rise in hash rate and Bitcoin network difficulty.
The first ASIC miners delivered around 1 TH/s—thousands of times more than typical CPUs, whose performance rarely exceeded 100 KH/s.