diff --git a/MANUAL.txt b/MANUAL.txt
index 29fc629cd..9fd0e3381 100644
--- a/MANUAL.txt
+++ b/MANUAL.txt
@@ -2637,7 +2637,10 @@ and lists, and cannot span multiple lines.  If a pipe table contains a
 row whose printable content is wider than the column width (see
 `--columns`), then the cell contents will wrap, with the
 relative cell widths determined by the widths of the separator
-lines.
+lines.  (In this case, the table will take up the full text
+width.)  If no lines are wider than column width, then
+cell contents will not be wrapped, and the cells will be sized
+to their contents.
 
 Note:  pandoc also recognizes pipe tables of the following
 form, as can be produced by Emacs' orgtbl-mode:
diff --git a/src/Text/Pandoc/Readers/Markdown.hs b/src/Text/Pandoc/Readers/Markdown.hs
index 2d7c12e99..b97a724a4 100644
--- a/src/Text/Pandoc/Readers/Markdown.hs
+++ b/src/Text/Pandoc/Readers/Markdown.hs
@@ -1353,8 +1353,8 @@ pipeTable = try $ do
   numColumns <- getOption readerColumns
   let widths = if maxlength > numColumns
                   then map (\len ->
-                           fromIntegral (len + 1) / fromIntegral numColumns)
-                             seplengths
+                         fromIntegral (len + 1) / fromIntegral (sum seplengths))
+                         seplengths
                   else replicate (length aligns) 0.0
   return (aligns, widths, heads', sequence lines'')
 
diff --git a/test/pipe-tables.native b/test/pipe-tables.native
index 63c2c17bc..6e39dc475 100644
--- a/test/pipe-tables.native
+++ b/test/pipe-tables.native
@@ -85,7 +85,7 @@
  ,[[Plain [Str "4"]]
   ,[Plain [Str "44"]]]]
 ,Para [Str "Long",Space,Str "pipe",Space,Str "table",Space,Str "with",Space,Str "relative",Space,Str "widths:"]
-,Table [] [AlignDefault,AlignDefault,AlignDefault] [0.125,0.1375,0.5]
+,Table [] [AlignDefault,AlignDefault,AlignDefault] [0.1639344262295082,0.18032786885245902,0.6557377049180328]
  [[Plain [Str "Default1"]]
  ,[Plain [Str "Default2"]]
  ,[Plain [Str "Default3"]]]