diff --git a/doc/mlr.1.premade b/doc/mlr.1.premade
index 7a1753fae..4877ece19 100644
--- a/doc/mlr.1.premade
+++ b/doc/mlr.1.premade
@@ -879,7 +879,8 @@ by category.
 -d {x,y,z} Weights for ewma. 1 means current sample gets all weight (no
            smoothing), near under under 1 is light smoothing, near over 0 is
            heavy smoothing. Multiple weights may be specified, e.g.
-           "mlr step -a ewma -f sys_load -d 0.01,0.1,0.9".
+           "mlr step -a ewma -f sys_load -d 0.01,0.1,0.9". Default if omitted
+           is "-d 0.5".
 Please see http://johnkerl.org/miller/doc/reference.html#filter or
 https://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average
 for more information on EWMA.
diff --git a/doc/reference.html b/doc/reference.html
index 8bf69e881..265f723c1 100644
--- a/doc/reference.html
+++ b/doc/reference.html
@@ -2807,7 +2807,8 @@ by category.
 -d {x,y,z} Weights for ewma. 1 means current sample gets all weight (no
            smoothing), near under under 1 is light smoothing, near over 0 is
            heavy smoothing. Multiple weights may be specified, e.g.
-           "mlr step -a ewma -f sys_load -d 0.01,0.1,0.9".
+           "mlr step -a ewma -f sys_load -d 0.01,0.1,0.9". Default if omitted
+           is "-d 0.5".
 Please see http://johnkerl.org/miller/doc/reference.html#filter or
 https://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average
 for more information on EWMA.