diff --git a/Framework/Units/PhysicalUnits.h b/Framework/Units/PhysicalUnits.h
index ffdb24805af772c7121cb5cf151a39bec921c73f..c7a3c2f7d4e1e8151be6203c522de79225fdc205 100644
--- a/Framework/Units/PhysicalUnits.h
+++ b/Framework/Units/PhysicalUnits.h
@@ -115,7 +115,7 @@ namespace corsika::units::si {
            static_pow<q>(corsika::units::constants::c);
   }
 
-  template <typename DimFrom, typename DimTo>
+  template <typename DimTo, typename DimFrom>
   auto constexpr ConvertHEPToSI(quantity<DimFrom> q) {
     return ConversionFactorHEPToSI<DimFrom, DimTo>() * q;
   }
diff --git a/Framework/Units/testUnits.cc b/Framework/Units/testUnits.cc
index ecf2ec519fccc353c479fdfac4362cfcae452630..77274459c0ccf2dc19b4068a15d2bb5c2e66ce62 100644
--- a/Framework/Units/testUnits.cc
+++ b/Framework/Units/testUnits.cc
@@ -129,20 +129,14 @@ TEST_CASE("PhysicalUnits", "[Units]") {
   SECTION("HEP/SI conversion") {
     auto const invEnergy = 1 / 197.326978_MeV; // should be convertible to length or time
 
-    LengthType const length =
-        ConvertHEPToSI<decltype(invEnergy)::dimension_type, LengthType::dimension_type>(
-            invEnergy);
+    LengthType const length = ConvertHEPToSI<LengthType::dimension_type>(invEnergy);
     REQUIRE((length / 1_fm) == Approx(1));
 
-    TimeType const time =
-        ConvertHEPToSI<decltype(invEnergy)::dimension_type, TimeType::dimension_type>(
-            invEnergy);
+    TimeType const time = ConvertHEPToSI<TimeType::dimension_type>(invEnergy);
     REQUIRE((time / (1_fm / corsika::units::constants::c)) == Approx(1));
 
     auto const protonMass = 938.272'081'3_MeV; // convertible to mass or SI energy
-    MassType protonMassSI =
-        ConvertHEPToSI<decltype(protonMass)::dimension_type, MassType::dimension_type>(
-            protonMass);
+    MassType protonMassSI = ConvertHEPToSI<MassType::dimension_type>(protonMass);
     REQUIRE((protonMassSI / 1.672'621'898e-27_kg) == Approx(1));
     REQUIRE((protonMassSI / (1.007'276 * corsika::units::constants::u)) == Approx(1));
   }