diff --git a/README.html b/README.html
index d0ab62b..4a140c6 100644
--- a/README.html
+++ b/README.html
@@ -559,7 +559,7 @@ pre.rouge .gs {
 <div class="details">
 <span id="author" class="author">Brent Saner</span><br>
 <span id="email" class="email"><a href="mailto:bts@square-r00t.net">bts@square-r00t.net</a></span><br>
-<span id="revdate">Last rendered 2025-09-02 22:56:14 -0400</span>
+<span id="revdate">Last rendered 2025-09-03 01:37:56 -0400</span>
 </div>
 <div id="toc" class="toc2">
 <div id="toctitle">Table of Contents</div>
@@ -2953,7 +2953,7 @@ IPv6 does not require a header checksum.</p>
 	<span class="n">vtfTOffset</span>   <span class="kt">uint32</span> <span class="o">=</span> <span class="m">0x00000014</span> <span class="c">// 20</span>
 	<span class="n">vtfTFlagMask</span> <span class="kt">uint32</span> <span class="o">=</span> <span class="m">0x000000ff</span> <span class="c">// mask to 8 bits</span>
 
-	<span class="n">vtfFlowMask</span> <span class="kt">uint32</span> <span class="o">=</span> <span class="m">0x0000ffff</span>
+	<span class="n">vtfFlowMask</span> <span class="kt">uint32</span> <span class="o">=</span> <span class="m">0x000fffff</span> <span class="c">// 1048575</span>
 <span class="p">)</span>
 
 <span class="k">func</span> <span class="n">ToVTF</span><span class="p">(</span><span class="n">ver</span><span class="p">,</span> <span class="n">tc</span><span class="p">,</span> <span class="n">flow</span> <span class="kt">uint32</span><span class="p">)</span> <span class="p">(</span><span class="n">vtf</span> <span class="kt">uint32</span><span class="p">)</span> <span class="p">{</span>
diff --git a/examples/vtf.go b/examples/vtf.go
index 19d89d5..15b39cf 100644
--- a/examples/vtf.go
+++ b/examples/vtf.go
@@ -20,7 +20,7 @@ var (
 	vtfTOffset   uint32 = 0x00000014 // 20
 	vtfTFlagMask uint32 = 0x000000ff // mask to 8 bits
 
-	vtfFlowMask uint32 = 0x0000ffff
+	vtfFlowMask uint32 = 0x000fffff // 1048575
 )
 
 func ToVTF(ver, tc, flow uint32) (vtf uint32) {