What it computes: the Information Coefficient (IC) is the cross-sectional correlation between a signal's forecasts and the returns that follow. The rank IC (Spearman's ρ) is the conventional measure because it's robust to outliers and only assumes a monotonic relationship; the Pearson IC assumes linearity. New to this? Start with the Information Coefficient guide.
Open source — view or fork the calculator on GitHub (MIT, single dependency-free HTML file). Related tool: Signal Decay Calculator.
Predictions and realized returns
Paste two columns — your signal's predictions (forecast scores, any scale) and the realized forward returns for the same names. One value per line; rows are matched in order, so both columns must be the same length.