diff --git a/doc/fix_ave_time.html b/doc/fix_ave_time.html
index 77bc98d5e0..718ac72c7b 100644
--- a/doc/fix_ave_time.html
+++ b/doc/fix_ave_time.html
@@ -44,7 +44,9 @@
   <I>ave</I> args = <I>one</I> or <I>running</I> or <I>window M</I>
     one = output a new average value every Nfreq steps
     running = output cumulative average of all previous Nfreq steps
-    window M = output average of M most recent Nfreq steps 
+    window M = output average of M most recent Nfreq steps
+  <I>start</I> args = Nstart
+    Nstart = start averaging on this timestep 
 </PRE>
 
 </UL>
@@ -172,6 +174,11 @@ on step 10000 will be the average of the individual values on steps
 8000,9000,10000.  Outputs on early steps will average over less than M
 values if they are not available.
 </P>
+<P>The <I>start</I> keyword specifies what timestep averaging will begin on.
+The default is step 0.  Often this value is 0.0, so setting <I>start</I> to
+a larger value can avoid including a 0.0 in a running or windowed
+average.
+</P>
 <HR>
 
 <P><B>Restart, fix_modify, output, run start/stop, minimize info:</B>
@@ -209,6 +216,6 @@ ave/atom</A>
 </P>
 <P><B>Default:</B> none
 </P>
-<P>The option defaults no file output and ave = one.
+<P>The option defaults no file output, ave = one, and start = 0.
 </P>
 </HTML>
diff --git a/doc/fix_ave_time.txt b/doc/fix_ave_time.txt
index 0192370931..169abe4977 100644
--- a/doc/fix_ave_time.txt
+++ b/doc/fix_ave_time.txt
@@ -32,7 +32,9 @@ keyword = {file} or {ave} :l
   {ave} args = {one} or {running} or {window M}
     one = output a new average value every Nfreq steps
     running = output cumulative average of all previous Nfreq steps
-    window M = output average of M most recent Nfreq steps :pre
+    window M = output average of M most recent Nfreq steps
+  {start} args = Nstart
+    Nstart = start averaging on this timestep :pre
 :ule
 
 [Examples:]
@@ -159,6 +161,11 @@ on step 10000 will be the average of the individual values on steps
 8000,9000,10000.  Outputs on early steps will average over less than M
 values if they are not available.
 
+The {start} keyword specifies what timestep averaging will begin on.
+The default is step 0.  Often this value is 0.0, so setting {start} to
+a larger value can avoid including a 0.0 in a running or windowed
+average.
+
 :line
 
 [Restart, fix_modify, output, run start/stop, minimize info:]
@@ -196,4 +203,4 @@ ave/atom"_fix_ave_atom.html
 
 [Default:] none
 
-The option defaults no file output and ave = one.
+The option defaults no file output, ave = one, and start = 0.