diff --git a/src/corelib/global/qfloat16.h b/src/corelib/global/qfloat16.h
index 387735863e..e574ffed78 100644
--- a/src/corelib/global/qfloat16.h
+++ b/src/corelib/global/qfloat16.h
@@ -234,6 +234,14 @@ Q_CORE_EXPORT void qFloatFromFloat16(float *, const qfloat16 *, qsizetype length
     return (qAbs(f1 - f2) * 102.5f <= qMin(qAbs(f1), qAbs(f2)));
 }
 
+/*!
+  \internal
+*/
+[[nodiscard]] inline bool qFuzzyIsNull(qfloat16 f) noexcept
+{
+    return qAbs(static_cast<float>(f)) <= 0.001f;
+}
+
 [[nodiscard]] inline bool qIsNull(qfloat16 f) noexcept
 {
     return (f.b16 & static_cast<quint16>(0x7fff)) == 0;
@@ -300,14 +308,6 @@ inline qfloat16::operator float() const noexcept
 }
 #endif
 
-/*!
-  \internal
-*/
-[[nodiscard]] inline bool qFuzzyIsNull(qfloat16 f) noexcept
-{
-    return qAbs(static_cast<float>(f)) <= 0.001f;
-}
-
 /*
   qHypot compatibility; see ../kernel/qmath.h
 */
diff --git a/tests/auto/corelib/global/qfloat16/CMakeLists.txt b/tests/auto/corelib/global/qfloat16/CMakeLists.txt
index b2848846fa..1dbc95ec95 100644
--- a/tests/auto/corelib/global/qfloat16/CMakeLists.txt
+++ b/tests/auto/corelib/global/qfloat16/CMakeLists.txt
@@ -7,4 +7,6 @@
 qt_internal_add_test(tst_qfloat16
     SOURCES
         tst_qfloat16.cpp
+    PUBLIC_LIBRARIES
+        Qt::TestPrivate
 )
diff --git a/tests/auto/corelib/global/qfloat16/tst_qfloat16.cpp b/tests/auto/corelib/global/qfloat16/tst_qfloat16.cpp
index 96051cbe2c..71a05d3031 100644
--- a/tests/auto/corelib/global/qfloat16/tst_qfloat16.cpp
+++ b/tests/auto/corelib/global/qfloat16/tst_qfloat16.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2019 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Copyright (C) 2016 by Southwest Research Institute (R)
 ** Contact: https://www.qt.io/licensing/
 **
@@ -43,6 +43,8 @@ class tst_qfloat16: public QObject
 private slots:
     void fuzzyCompare_data();
     void fuzzyCompare();
+    void fuzzyIsNull_data();
+    void fuzzyIsNull();
     void ltgt_data();
     void ltgt();
     void qNaN();
@@ -111,6 +113,33 @@ void tst_qfloat16::fuzzyCompare()
     }
 }
 
+void tst_qfloat16::fuzzyIsNull_data()
+{
+    QTest::addColumn<qfloat16>("value");
+    QTest::addColumn<bool>("isNull");
+    using Bounds = std::numeric_limits<qfloat16>;
+    const qfloat16 one(1), huge(1000), tiny(0.00099f);
+
+    QTest::newRow("zero") << qfloat16(0.0f) << true;
+    QTest::newRow("min") << Bounds::min() << true;
+    QTest::newRow("denorm_min") << Bounds::denorm_min() << true;
+    QTest::newRow("tiny") << tiny << true;
+
+    QTest::newRow("deci") << qfloat16(.1) << false;
+    QTest::newRow("one") << one << false;
+    QTest::newRow("ten") << qfloat16(10) << false;
+    QTest::newRow("huge") << huge << false;
+}
+
+void tst_qfloat16::fuzzyIsNull()
+{
+    QFETCH(qfloat16, value);
+    QFETCH(bool, isNull);
+
+    QCOMPARE(::qFuzzyIsNull(value), isNull);
+    QCOMPARE(::qFuzzyIsNull(-value), isNull);
+}
+
 void tst_qfloat16::ltgt_data()
 {
     QTest::addColumn<float>("val1");
diff --git a/tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp b/tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp
index 0cfb8541ab..5b54eeae01 100644
--- a/tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp
+++ b/tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2019 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Copyright (C) 2016 Intel Corporation.
 ** Contact: https://www.qt.io/licensing/
 **
@@ -52,6 +52,8 @@ class tst_QNumeric: public QObject
     // Support for floating-point:
     template<typename F> inline void fuzzyCompare_data();
     template<typename F> inline void fuzzyCompare();
+    template<typename F> inline void fuzzyIsNull_data();
+    template<typename F> inline void fuzzyIsNull();
     template<typename F> inline void checkNaN(F nan);
     template<typename F> inline void rawNaN_data();
     template<typename F> inline void rawNaN();
@@ -71,6 +73,10 @@ private slots:
     void fuzzyCompareF() { fuzzyCompare<float>(); }
     void fuzzyCompareD_data() { fuzzyCompare_data<double>(); }
     void fuzzyCompareD() { fuzzyCompare<double>(); }
+    void fuzzyIsNullF_data() { fuzzyIsNull_data<float>(); }
+    void fuzzyIsNullF() { fuzzyIsNull<float>(); }
+    void fuzzyIsNullD_data() { fuzzyIsNull_data<double>(); }
+    void fuzzyIsNullD() { fuzzyIsNull<double>(); }
     void rawNaNF_data() { rawNaN_data<float>(); }
     void rawNaNF() { rawNaN<float>(); }
     void rawNaND_data() { rawNaN_data<double>(); }
@@ -143,6 +149,36 @@ void tst_QNumeric::fuzzyCompare()
     QCOMPARE(::qFuzzyCompare(-val2, -val1), isEqual);
 }
 
+template<typename F>
+void tst_QNumeric::fuzzyIsNull_data()
+{
+    QTest::addColumn<F>("value");
+    QTest::addColumn<bool>("isNull");
+    using Bounds = std::numeric_limits<F>;
+    const F one(1), huge = Fuzzy<F>::scale, tiny = one / huge;
+
+    QTest::newRow("zero") << F(0) << true;
+    QTest::newRow("min") << Bounds::min() << true;
+    QTest::newRow("denorm_min") << Bounds::denorm_min() << true;
+    QTest::newRow("tiny") << tiny << true;
+
+    QTest::newRow("deci") << F(.1) << false;
+    QTest::newRow("one") << one << false;
+    QTest::newRow("ten") << F(10) << false;
+    QTest::newRow("large") << F(1e9) << false;
+    QTest::newRow("huge") << huge << false;
+}
+
+template<typename F>
+void tst_QNumeric::fuzzyIsNull()
+{
+    QFETCH(F, value);
+    QFETCH(bool, isNull);
+
+    QCOMPARE(::qFuzzyIsNull(value), isNull);
+    QCOMPARE(::qFuzzyIsNull(-value), isNull);
+}
+
 #if defined __FAST_MATH__ && (__GNUC__ * 100 + __GNUC_MINOR__ >= 404)
    // turn -ffast-math off
 #  pragma GCC optimize "no-fast-math"