diff --git a/docs/api-output.md b/docs/api-output.md
index a29d5119..a7c0209b 100644
--- a/docs/api-output.md
+++ b/docs/api-output.md
@@ -161,7 +161,7 @@ sharp('input.tiff')
   .tile({
     size: 512
   })
-  .toFile('output.dzi', function(err, info) {
+  .toFile('output.dz', function(err, info) {
     // output.dzi is the Deep Zoom XML definition
     // output_files contains 512x512 tiles grouped by zoom level
   });
diff --git a/lib/output.js b/lib/output.js
index a10feb96..75655e17 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -237,7 +237,7 @@ const toFormat = function toFormat (format, options) {
  *   .tile({
  *     size: 512
  *   })
- *   .toFile('output.dzi', function(err, info) {
+ *   .toFile('output.dz', function(err, info) {
  *     // output.dzi is the Deep Zoom XML definition
  *     // output_files contains 512x512 tiles grouped by zoom level
  *   });