diff --git a/files/usr/share/ucode/aredn/units.uc b/files/usr/share/ucode/aredn/units.uc
index d50d1b06..a73fd4be 100755
--- a/files/usr/share/ucode/aredn/units.uc
+++ b/files/usr/share/ucode/aredn/units.uc
@@ -38,7 +38,7 @@ let metric = null;
 function isMetric()
 {
     if (metric === null) {
-        const lang = request?.env?.HTTP_ACCEPT_LANGUAGE || "en-US";
+        const lang = split(request?.env?.HTTP_ACCEPT_LANGUAGE || "en-US", ",")[0];
         if (index(lang, "-US") !== -1 || index(lang, "-GB") !== -1) {
             metric = false;
         }