diff --git a/index.browser.js b/index.browser.js
index 09368f33..7ab1562c 100644
--- a/index.browser.js
+++ b/index.browser.js
@@ -61,10 +61,10 @@ let nanoid = (size = 21) =>
     } else if (byte < 62) {
       // `A-Z`
       id += (byte - 26).toString(36).toUpperCase()
-    } else if (byte < 63) {
-      id += '_'
-    } else {
+    } else if (byte > 62) {
       id += '-'
+    } else {
+      id += '_'
     }
     return id
   }, '')
diff --git a/package.json b/package.json
index f59a441f..cd0099e1 100644
--- a/package.json
+++ b/package.json
@@ -108,7 +108,7 @@
       "name": "Brotli all",
       "brotli": true,
       "import": "{ nanoid, customAlphabet, urlAlphabet }",
-      "limit": "264 B"
+      "limit": "260 B"
     },
     {
       "name": "Brotli non-secure",