diff --git a/public_html/registrations.js b/public_html/registrations.js
index 1fab589..1d5c50f 100644
--- a/public_html/registrations.js
+++ b/public_html/registrations.js
@@ -92,7 +92,7 @@ registration_from_hexid = (function () {
                         mapping.end = mapping.start - mapping.offset +
                                 c1 * mapping.s1 +
                                 c2 * mapping.s2 +
-                                c3 - mapping.offset;
+                                c3;
                 } else {
                         mapping.end = mapping.start - mapping.offset +
                                 (mapping.alphabet.length - 1) * mapping.s1 +