diff --git a/doc/effective_go.html b/doc/effective_go.html
index 8083e9fbc9..a04152e49c 100644
--- a/doc/effective_go.html
+++ b/doc/effective_go.html
@@ -1539,26 +1539,29 @@ automatically for printing, even as part of a general type.
 func (b ByteSize) String() string {
     switch {
     case b >= YB:
-        return fmt.Sprintf("%.2fYB", b/YB)
+        return fmt.Sprintf("%.2fYB", float64(b/YB))
     case b >= ZB:
-        return fmt.Sprintf("%.2fZB", b/ZB)
+        return fmt.Sprintf("%.2fZB", float64(b/ZB))
     case b >= EB:
-        return fmt.Sprintf("%.2fEB", b/EB)
+        return fmt.Sprintf("%.2fEB", float64(b/EB))
     case b >= PB:
-        return fmt.Sprintf("%.2fPB", b/PB)
+        return fmt.Sprintf("%.2fPB", float64(b/PB))
     case b >= TB:
-        return fmt.Sprintf("%.2fTB", b/TB)
+        return fmt.Sprintf("%.2fTB", float64(b/TB))
     case b >= GB:
-        return fmt.Sprintf("%.2fGB", b/GB)
+        return fmt.Sprintf("%.2fGB", float64(b/GB))
     case b >= MB:
-        return fmt.Sprintf("%.2fMB", b/MB)
+        return fmt.Sprintf("%.2fMB", float64(b/MB))
     case b >= KB:
-        return fmt.Sprintf("%.2fKB", b/KB)
+        return fmt.Sprintf("%.2fKB", float64(b/KB))
     }
-    return fmt.Sprintf("%.2fB", b)
+    return fmt.Sprintf("%.2fB", float64(b))
 }
 </pre>
 <p>
+(The <code>float64</code> conversions prevent <code>Sprintf</code> 
+from recurring back through the <code>String</code> method for 
+<code>ByteSize</code>.)
 The expression <code>YB</code> prints as <code>1.00YB</code>,
 while <code>ByteSize(1e13)</code> prints as <code>9.09TB</code>.
 </p>