diff --git a/README.asciidoc b/README.asciidoc
index 42d79dc..c5e1f7a 100644
--- a/README.asciidoc
+++ b/README.asciidoc
@@ -293,7 +293,7 @@ Options
     Preselect the splitting area of the selected window (or cancel the preselection).
 
 *-r*, *--ratio* 'RATIO'::
-    Set the splitting ratio of the selected window.
+    Set the splitting ratio of the selected window (0 < 'RATIO' < 1).
 
 *-e*, *--edge* 'DIR' 'RATIO'|pull|push::
     Set the splitting ratio (or pull, or push) the edge located in the given direction in relation to the selected window.
diff --git a/doc/bspwm.1 b/doc/bspwm.1
index 2bfa126..0e376e3 100644
--- a/doc/bspwm.1
+++ b/doc/bspwm.1
@@ -2,12 +2,12 @@
 .\"     Title: bspwm
 .\"    Author: [see the "Author" section]
 .\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
-.\"      Date: 07/19/2013
+.\"      Date: 07/23/2013
 .\"    Manual: Bspwm Manual
 .\"    Source: Bspwm 0.7
 .\"  Language: English
 .\"
-.TH "BSPWM" "1" "07/19/2013" "Bspwm 0\&.7" "Bspwm Manual"
+.TH "BSPWM" "1" "07/23/2013" "Bspwm 0\&.7" "Bspwm Manual"
 .\" -----------------------------------------------------------------
 .\" * Define some portability stuff
 .\" -----------------------------------------------------------------
@@ -446,7 +446,9 @@ Preselect the splitting area of the selected window (or cancel the preselection)
 .PP
 \fB\-r\fR, \fB\-\-ratio\fR \fIRATIO\fR
 .RS 4
-Set the splitting ratio of the selected window\&.
+Set the splitting ratio of the selected window (0 <
+\fIRATIO\fR
+< 1)\&.
 .RE
 .PP
 \fB\-e\fR, \fB\-\-edge\fR \fIDIR\fR \fIRATIO\fR|pull|push
diff --git a/doc/bspwm.1.txt b/doc/bspwm.1.txt
index 9e35013..9e9d3c3 100644
--- a/doc/bspwm.1.txt
+++ b/doc/bspwm.1.txt
@@ -291,7 +291,7 @@ Options
     Preselect the splitting area of the selected window (or cancel the preselection).
 
 *-r*, *--ratio* 'RATIO'::
-    Set the splitting ratio of the selected window.
+    Set the splitting ratio of the selected window (0 < 'RATIO' < 1).
 
 *-e*, *--edge* 'DIR' 'RATIO'|pull|push::
     Set the splitting ratio (or pull, or push) the edge located in the given direction in relation to the selected window.