diff --git a/src/blackmisc/pq/measurementunit.h b/src/blackmisc/pq/measurementunit.h
index 05120ac2a..c51202acf 100644
--- a/src/blackmisc/pq/measurementunit.h
+++ b/src/blackmisc/pq/measurementunit.h
@@ -146,12 +146,11 @@ namespace BlackMisc
                 {
                     using BlackMisc::Math::CMathUtils;
                     double part1 = CMathUtils::trunc(factor / FactorPolicy::factor());
-                    double remaining = std::fmod(factor, FactorPolicy::factor());
-                    double part2 = CMathUtils::trunc(remaining / SubdivPolicy::subfactor());
-                    remaining = std::fmod(remaining, SubdivPolicy::subfactor());
-                    double part3 = CMathUtils::trunc(remaining / SubdivPolicy::subfactor());
-                    remaining = std::fmod(remaining, SubdivPolicy::subfactor());
-                    return part1 + part2 / SubdivPolicy::fraction() + (part3 + remaining) / (SubdivPolicy::fraction() * SubdivPolicy::fraction());
+                    double remaining = std::fmod(factor / FactorPolicy::factor(), 1.0);
+                    double part2 = CMathUtils::trunc(remaining * SubdivPolicy::subfactor());
+                    remaining = std::fmod(remaining * SubdivPolicy::subfactor(), 1.0);
+                    double part3 = remaining * SubdivPolicy::subfactor();
+                    return part1 + part2 / SubdivPolicy::fraction() + part3 / (SubdivPolicy::fraction() * SubdivPolicy::fraction());
                 }
             };
 
diff --git a/tests/blackmisc/testphysicalquantities.cpp b/tests/blackmisc/testphysicalquantities.cpp
index 49198e4cb..759ee9a16 100644
--- a/tests/blackmisc/testphysicalquantities.cpp
+++ b/tests/blackmisc/testphysicalquantities.cpp
@@ -105,6 +105,12 @@ namespace BlackMiscTest
         QVERIFY2(CMathUtils::epsilonEqual(a3.valueRounded(CAngleUnit::deg()), 35.73), "Expecting 35.73");
         QVERIFY2(CMathUtils::epsilonEqual(a4.valueRounded(CAngleUnit::deg()), 35.73), "Expecting 35.73");
         QVERIFY2(CMathUtils::epsilonEqual(a5.valueRounded(CAngleUnit::deg(), 4), -60.5042), "Expecting -60.5042");
+
+        // issue #552
+        CAngle a6(48.07063588, CAngleUnit::sexagesimalDeg());
+        CAngle a7(a6);
+        a7.switchUnit(CAngleUnit::rad());
+        QVERIFY2(CMathUtils::epsilonEqual(a6.value(CAngleUnit::sexagesimalDeg()), a7.value(CAngleUnit::sexagesimalDeg())), "Conversion via radians yields same answer");
     }
 
     /*