diff --git a/src/common/QskIntervalF.h b/src/common/QskIntervalF.h
index 8feb31bd..30fa222d 100644
--- a/src/common/QskIntervalF.h
+++ b/src/common/QskIntervalF.h
@@ -76,6 +76,7 @@ class QSK_EXPORT QskIntervalF
 
     constexpr bool isValid() const noexcept;
     constexpr bool isNull() const noexcept;
+    constexpr bool isEmpty() const noexcept;
 
     void invalidate() noexcept;
 
@@ -149,6 +150,11 @@ inline constexpr bool QskIntervalF::isNull() const noexcept
     return m_lowerBound == m_upperBound;
 }
 
+inline constexpr bool QskIntervalF::isEmpty() const noexcept
+{
+    return m_upperBound <= m_lowerBound;
+}
+
 inline void QskIntervalF::invalidate() noexcept
 {
     m_lowerBound = 0.0;