diff --git a/include/android-base/parsedouble.h b/include/android-base/parsedouble.h
index c273c61..9a20eb1 100644
--- a/include/android-base/parsedouble.h
+++ b/include/android-base/parsedouble.h
@@ -24,7 +24,7 @@
 namespace android {
 namespace base {
 
-// Parse double value in the string 's' and sets 'out' to that value.
+// Parse double value in the string 's' and sets 'out' to that value if it exists.
 // Optionally allows the caller to define a 'min' and 'max' beyond which
 // otherwise valid values will be rejected. Returns boolean success.
 static inline bool ParseDouble(const char* s, double* out,
@@ -39,7 +39,9 @@
   if (result < min || max < result) {
     return false;
   }
-  *out = result;
+  if (out != nullptr) {
+    *out = result;
+  }
   return true;
 }
 
diff --git a/include/android-base/parseint.h b/include/android-base/parseint.h
index bb54c99..55f1ed3 100644
--- a/include/android-base/parseint.h
+++ b/include/android-base/parseint.h
@@ -27,9 +27,9 @@
 namespace base {
 
 // Parses the unsigned decimal or hexadecimal integer in the string 's' and sets
-// 'out' to that value. Optionally allows the caller to define a 'max' beyond
-// which otherwise valid values will be rejected. Returns boolean success; 'out'
-// is untouched if parsing fails.
+// 'out' to that value if it is specified. Optionally allows the caller to define
+// a 'max' beyond which otherwise valid values will be rejected. Returns boolean
+// success; 'out' is untouched if parsing fails.
 template <typename T>
 bool ParseUint(const char* s, T* out, T max = std::numeric_limits<T>::max(),
                bool allow_suffixes = false) {
@@ -72,9 +72,9 @@
 }
 
 // Parses the signed decimal or hexadecimal integer in the string 's' and sets
-// 'out' to that value. Optionally allows the caller to define a 'min' and 'max'
-// beyond which otherwise valid values will be rejected. Returns boolean
-// success; 'out' is untouched if parsing fails.
+// 'out' to that value if it is specified. Optionally allows the caller to define
+// a 'min' and 'max' beyond which otherwise valid values will be rejected. Returns
+// boolean success; 'out' is untouched if parsing fails.
 template <typename T>
 bool ParseInt(const char* s, T* out,
               T min = std::numeric_limits<T>::min(),
diff --git a/parsedouble_test.cpp b/parsedouble_test.cpp
index 8734c42..797a370 100644
--- a/parsedouble_test.cpp
+++ b/parsedouble_test.cpp
@@ -35,4 +35,9 @@
   ASSERT_FALSE(android::base::ParseDouble("3.0", &d, -1.0, 2.0));
   ASSERT_TRUE(android::base::ParseDouble("1.0", &d, 0.0, 2.0));
   ASSERT_DOUBLE_EQ(1.0, d);
+
+  ASSERT_FALSE(android::base::ParseDouble("123.4x", nullptr));
+  ASSERT_TRUE(android::base::ParseDouble("-123.4", nullptr));
+  ASSERT_FALSE(android::base::ParseDouble("3.0", nullptr, -1.0, 2.0));
+  ASSERT_TRUE(android::base::ParseDouble("1.0", nullptr, 0.0, 2.0));
 }