Volcano plot maker

Each point is a gene. The x-axis is the log2 fold change (right = up, left = down); the y-axis is −log10 of the chosen P value column (usually the adjusted P value), so higher means more significant.

Dashed lines mark your thresholds: points beyond both lines count as up (red) or down (blue); all others are grey.

Thresholds drive the counts, so keep them identical to those stated in your methods. Genes without an adjusted P value (for example low-count genes removed by independent filtering) are not plotted; the page shows how many rows were skipped.

A volcano plot shows statistical significance and effect size, not biological function; interpret candidate genes together with enrichment analysis and experimental validation.

Method

Up: P below the threshold and log2FC above it; down: P below the threshold and log2FC below its negative. The y-axis is −log10(P) of the chosen P value column (usually the adjusted P value); P = 0 is shown at one tenth of the smallest non-zero P.

Data size

Above 5,000 points the chart switches to canvas drawing.