diff --git a/include/libcamera/geometry.h b/include/libcamera/geometry.h
index edda42cf3..7d4b8bcfe 100644
--- a/include/libcamera/geometry.h
+++ b/include/libcamera/geometry.h
@@ -41,6 +41,7 @@ struct Size {
 	unsigned int width;
 	unsigned int height;
 
+	bool isNull() const { return !width && !height; }
 	const std::string toString() const;
 };
 
diff --git a/src/libcamera/geometry.cpp b/src/libcamera/geometry.cpp
index fd78cf2c0..24c44fb43 100644
--- a/src/libcamera/geometry.cpp
+++ b/src/libcamera/geometry.cpp
@@ -107,6 +107,12 @@ bool operator==(const Rectangle &lhs, const Rectangle &rhs)
  * \brief The Size height
  */
 
+/**
+ * \fn bool Size::isNull() const
+ * \brief Check if the size is null
+ * \return True if both the width and height are 0, or false otherwise
+ */
+
 /**
  * \brief Assemble and return a string describing the size
  * \return A string describing the size
diff --git a/test/geometry.cpp b/test/geometry.cpp
index 27e65565d..904ad92c9 100644
--- a/test/geometry.cpp
+++ b/test/geometry.cpp
@@ -36,6 +36,16 @@ protected:
 
 	int run()
 	{
+		if (!Size().isNull() || !Size(0, 0).isNull()) {
+			cout << "Null size incorrectly reported as not null" << endl;
+			return TestFail;
+		}
+
+		if (Size(0, 100).isNull() || Size(100, 0).isNull() || Size(100, 100).isNull()) {
+			cout << "Non-null size incorrectly reported as null" << endl;
+			return TestFail;
+		}
+
 		/* Test Size equality and inequality. */
 		if (!compare(Size(100, 100), Size(100, 100), &operator==, "==", true))
 			return TestFail;