Why Bitcoin's "Years" Don't Align with the Calendar

When looking at Bitcoin's price history on a chart scaled by the number of blocks mined (the "h-scale"), you might notice something odd: calendar years appear to have different lengths. This isn't an error. It highlights a fascinating aspect of how Bitcoin's internal clock works.

As you can see in the chart, the markers for calendar years (2010, 2011, etc.) do not line up in perfectly equal intervals. This is because the x-axis doesn't measure time in days, but in the number of blocks successfully mined.

The Cause: Hash Rate vs. Difficulty

The Bitcoin network is designed to produce a new block approximately every 10 minutes. To maintain this pace, the mining difficulty automatically adjusts every 2016 blocks (roughly every two weeks).

However, the network's total computing power, known as the hash rate, is constantly changing. Throughout most of Bitcoin's history, the hash rate has been in a strong uptrend.

When the hash rate increases between difficulty adjustments, blocks are found faster than the 10-minute target. This causes more blocks to be mined in a given period than theoretically expected.

The Data Proves It

The theoretical number of blocks in a year is about 52,560 (6 blocks/hour * 24 hours/day * 365 days/year). This is often rounded to 52.5k, aligning with the halving cycle of 210,000 blocks every four years.