A funnel plot is a scatter plot used in meta-analysis to compare each study's effect estimate with a measure of precision, commonly its standard error. Larger, more precise studies appear near the top, while smaller studies spread more widely toward the bottom.
When sampling variation is the main source of scatter, study points often form a roughly symmetrical inverted funnel around the pooled effect. Visible asymmetry is commonly investigated as a small-study effect, but it can also arise from heterogeneity, outcome selection, methodological differences, or chance.
This Funnel Plot Maker calculates inverse-variance fixed or DerSimonian–Laird random-effects summaries. It can derive precision from standard error, variance, or a 95% confidence interval and keeps ratio measures on the log scale during analysis.
Effect estimate
One MD, SMD, OR, RR, HR, or generic estimate per study.
Precision
Standard error, variance, or lower and upper 95% limits.
Reversed SE axis
More precise studies appear at the top of the funnel.
Cautious interpretation
Asymmetry prompts investigation; it does not prove bias.











