This webpage tracks the historical correlation between different assets. It uses the Pearson correlation coefficient. I built this page because I would always get frustrated when trying to find Bitcoin and Ethereum correlation charts on the internet. The correlations are calculated over several rolling time horizons. The charts are based on daily closing prices over the past five years. Correlation is a statistical measure that expresses the extent to which two variables move in relation to each other. If the two assets have a positive correlation, it means the prices of both assets tend to move in the same direction. Conversely, if the correlation is negative, the prices of the assets tend to move in opposite directions.
This code is open source and can be found here: https://github.com/josusanmartin/correlations