diff --git a/zedai-to-epub3/src/main/resources/xml/xproc/zedai-to-epub3.convert.xpl b/zedai-to-epub3/src/main/resources/xml/xproc/zedai-to-epub3.convert.xpl
index be10a2521..b56cff961 100755
--- a/zedai-to-epub3/src/main/resources/xml/xproc/zedai-to-epub3.convert.xpl
+++ b/zedai-to-epub3/src/main/resources/xml/xproc/zedai-to-epub3.convert.xpl
@@ -24,6 +24,7 @@
     </p:output>
 
     <p:option name="output-dir" required="true"/>
+    <p:option name="chunk-size" required="false" select="'-1'"/>
     <p:option name="audio" required="false" select="'false'"/>
 
     <p:import href="http://www.daisy.org/pipeline/modules/html-utils/library.xpl"/>
@@ -178,7 +179,9 @@
                 <p:empty/>
             </p:input>
         </p:xslt>
-        <px:html-chunker name="zedai-to-html.html-chunks"/>
+        <px:html-chunker name="zedai-to-html.html-chunks">
+            <p:with-option name="chunk-size" select="$chunk-size"/>
+        </px:html-chunker>
         <p:for-each name="zedai-to-html.iterate">
             <p:output port="fileset" primary="true"/>
             <p:output port="html-files" sequence="true">
diff --git a/zedai-to-epub3/src/main/resources/xml/xproc/zedai-to-epub3.xpl b/zedai-to-epub3/src/main/resources/xml/xproc/zedai-to-epub3.xpl
index 167705397..620edf23c 100755
--- a/zedai-to-epub3/src/main/resources/xml/xproc/zedai-to-epub3.xpl
+++ b/zedai-to-epub3/src/main/resources/xml/xproc/zedai-to-epub3.xpl
@@ -49,6 +49,16 @@
       </p:documentation>
     </p:option>
 
+    <p:option name="chunk-size" required="false" px:type="integer" select="'-1'">
+      <p:documentation xmlns="http://www.w3.org/1999/xhtml">
+        <h2 px:role="name">Chunk size</h2>
+        <p px:role="desc" xml:space="preserve">The maximum size of HTML files in kB. Specify "-1" for no maximum.
+
+Top-level sections in the ZedAI become separate HTML files in the resulting EPUB. Each of these HTML files is
+further split up if they exceed the given maximum size.</p>
+      </p:documentation>
+    </p:option>
+
     <p:import href="zedai-to-epub3.convert.xpl"/>
 
     <p:import href="http://www.daisy.org/pipeline/modules/epub3-nav-utils/library.xpl"/>