Correlation measures how two assets move together, from -1 (opposite) to +1 (identical). Holding five coins that all correlate at 0.9 is barely diversified - in a sell-off they drop together. This tool builds a Pearson correlation matrix from real daily prices; green/blue cells are low correlation (good), red cells are high (little diversification).
How the correlation is calculated
We fetch daily closing prices for each coin from a public exchange API, convert them to daily returns (percentage change day over day), align the series on common dates, and compute the Pearson correlation coefficient for every pair. The result is a symmetric matrix where the diagonal is always 1.0 (a coin is perfectly correlated with itself).
Returns - not raw prices - are the right input: two assets can both trend up yet move on different days. Correlating returns captures whether they actually rise and fall together. If a coin can't be loaded, the tool tells you plainly and computes nothing - it never invents data.
Reading the heatmap
Each cell is colored on a scale: green/blue means low correlation (good diversification), red means high correlation (the assets move as one). A negative value - rare in crypto - is the best case for diversification. The average off-diagonal correlation, shown below the matrix, is a quick portfolio-level read.
- Below 0.5 - meaningfully diversified.
- 0.5 to 0.8 - partial; expect them to move together often.
- Above 0.8 - effectively one position split across tickers.
Why correlation is not a guarantee
Crypto correlations are historical and regime-dependent. In calm markets altcoins can decouple, but in sharp sell-offs almost everything correlates toward 1 with Bitcoin - exactly when you were counting on diversification to protect you. A short 30-day window is also noisy; 90 or 180 days is more stable but slower to react to regime change.
Use this as one input, not a promise. For position-level risk, pair it with the DCA calculator and the exchange comparison. Only public price requests are sent; nothing is stored.
