diff --git a/pkgs/by-name/si/sipcalc/package.nix b/pkgs/by-name/si/sipcalc/package.nix
index 76374fa087fa..34155824ec24 100644
--- a/pkgs/by-name/si/sipcalc/package.nix
+++ b/pkgs/by-name/si/sipcalc/package.nix
@@ -9,7 +9,7 @@ stdenv.mkDerivation (finalAttrs: {
   version = "1.1.6";
 
   src = fetchurl {
-    url = "http://www.routemeister.net/projects/sipcalc/files/sipcalc-${finalAttrs.version}.tar.gz";
+    url = "https://www.routemeister.net/projects/sipcalc/files/sipcalc-${finalAttrs.version}.tar.gz";
     sha256 = "cfd476c667f7a119e49eb5fe8adcfb9d2339bc2e0d4d01a1d64b7c229be56357";
   };