What is the formula for Bitcoin difficulty algorithm?

The current BTC difficulty is 27.45 T at block 729,040, resulting in a Bitcoin mining difficulty increase of 0.00% in the last 24 hours. The Bitcoin difficulty chart plots the Bitcoin difficulty target over time and the current Bitcoin difficulty (BTC diff) target.

The difficulty adjusts every 2016 blocks. Approximate number of blocks per day is: 6 blocks per hour X 24 hours = 144 blocks . 2016 blocks / 144 blocks per day = 14 days. Approximately every two weeks the difficulty adjusts.29 Nis 2018

The Ethereum difficulty data levels are calculated using the daily difficulty average data points in the Ethereum difficulty graph .

The difficulty is automatically adjusted based the amount of computational power on the network, or hashrate , to keep the time it takes to mine a block roughly stable at 10 minutes. The higher the hashrate, the higher the difficulty, and vice versa.