diff --git a/src/eigenvalue.F90 b/src/eigenvalue.F90
index fc44489d00..82ad2d73a4 100644
--- a/src/eigenvalue.F90
+++ b/src/eigenvalue.F90
@@ -616,7 +616,7 @@ contains
         if (confidence_intervals) then
           ! Calculate t-value for confidence intervals
           alpha = ONE - CONFIDENCE_LEVEL
-          t_value = t_percentile(ONE - alpha/TWO, n_realizations - 1)
+          t_value = t_percentile(ONE - alpha/TWO, n - 1)
         else
           t_value = ONE
         end if