diff --git a/doc/variable.html b/doc/variable.html
index 358826aa81..fbb3d47f47 100644
--- a/doc/variable.html
+++ b/doc/variable.html
@@ -21,11 +21,23 @@
 
 <PRE>  <I>delete</I> = no args
   <I>index</I> args = one or more strings
-  <I>loop</I> args = N = integer size of loop, loop from 1 to N inclusive
-  <I>loop</I> args = N1 N2 = loop from N1 to N2 inclusive
+  <I>loop</I> args = N
+    N = integer size of loop, loop from 1 to N inclusive
+  <I>loop</I> args = N pad
+    N = integer size of loop, loop from 1 to N inclusive
+    pad = all values will be same length, e.g. 001, 002, ..., 100
+  <I>loop</I> args = N1 N2
+    N1,N2 = loop from N1 to N2 inclusive
+  <I>loop</I> args = N1 N2 pad
+    N1,N2 = loop from N1 to N2 inclusive
+    pad = all values will be same length, e.g. 050, 051, ..., 100
   <I>world</I> args = one string for each partition of processors
   <I>universe</I> args = one or more strings
-  <I>uloop</I> args = N = integer size of loop
+  <I>uloop</I> args = N
+    N = integer size of loop
+  <I>uloop</I> args = N pad
+    N = integer size of loop
+    pad = all values will be same length, e.g. 001, 002, ..., 100
   <I>string</I> arg = one string
   <I>equal</I> or <I>atom</I> args = one formula containing numbers, thermo keywords, math operations, group functions, atom values and vectors, compute/fix/variable references
     numbers = 0.0, 100, -5.4, 2.8e-4, etc
@@ -65,7 +77,7 @@ variable b atom x*y/vol
 variable foo myfile
 variable temp world 300.0 310.0 320.0 ${Tfinal}
 variable x universe 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
-variable x uloop 15
+variable x uloop 15 pad
 variable x delete 
 </PRE>
 <P><B>Description:</B>
diff --git a/doc/variable.txt b/doc/variable.txt
index 424fc81818..578ac99a2f 100644
--- a/doc/variable.txt
+++ b/doc/variable.txt
@@ -16,11 +16,23 @@ name = name of variable to define :ulb,l
 style = {delete} or {index} or {loop} or {world} or {universe} or {uloop} or {string} or {equal} or {atom} :l
   {delete} = no args
   {index} args = one or more strings
-  {loop} args = N = integer size of loop, loop from 1 to N inclusive
-  {loop} args = N1 N2 = loop from N1 to N2 inclusive
+  {loop} args = N
+    N = integer size of loop, loop from 1 to N inclusive
+  {loop} args = N pad
+    N = integer size of loop, loop from 1 to N inclusive
+    pad = all values will be same length, e.g. 001, 002, ..., 100
+  {loop} args = N1 N2
+    N1,N2 = loop from N1 to N2 inclusive
+  {loop} args = N1 N2 pad
+    N1,N2 = loop from N1 to N2 inclusive
+    pad = all values will be same length, e.g. 050, 051, ..., 100
   {world} args = one string for each partition of processors
   {universe} args = one or more strings
-  {uloop} args = N = integer size of loop
+  {uloop} args = N
+    N = integer size of loop
+  {uloop} args = N pad
+    N = integer size of loop
+    pad = all values will be same length, e.g. 001, 002, ..., 100
   {string} arg = one string
   {equal} or {atom} args = one formula containing numbers, thermo keywords, math operations, group functions, atom values and vectors, compute/fix/variable references
     numbers = 0.0, 100, -5.4, 2.8e-4, etc
@@ -59,7 +71,7 @@ variable b atom x*y/vol
 variable foo myfile
 variable temp world 300.0 310.0 320.0 $\{Tfinal\}
 variable x universe 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
-variable x uloop 15
+variable x uloop 15 pad
 variable x delete :pre
 
 [Description:]