diff --git a/include/boost/charconv/detail/from_chars_integer_impl.hpp b/include/boost/charconv/detail/from_chars_integer_impl.hpp
index c9aa7e2..60b653c 100644
--- a/include/boost/charconv/detail/from_chars_integer_impl.hpp
+++ b/include/boost/charconv/detail/from_chars_integer_impl.hpp
@@ -99,7 +99,7 @@ BOOST_CXX14_CONSTEXPR from_chars_result from_chars_integer_impl(const char* firs
                 is_negative = true;
                 ++next;
             }
-            else if (*next == '+')
+            else if (*next == '+' || *next == ' ')
             {
                 return {next, std::errc::invalid_argument};
             }
@@ -126,7 +126,7 @@ BOOST_CXX14_CONSTEXPR from_chars_result from_chars_integer_impl(const char* firs
     }
     else
     {
-        if (next != last && (*next == '-' || *next == '+'))
+        if (next != last && (*next == '-' || *next == '+' || *next == ' '))
         {
             return {first, std::errc::invalid_argument};
         }
diff --git a/test/from_chars.cpp b/test/from_chars.cpp
index 09ed366..738899a 100644
--- a/test/from_chars.cpp
+++ b/test/from_chars.cpp
@@ -183,6 +183,18 @@ void invalid_argument_test()
     auto r7 = boost::charconv::from_chars(buffer7, buffer7 + std::strlen(buffer7), v7);
     BOOST_TEST(r7.ec == std::errc::invalid_argument);
     BOOST_TEST_EQ(v7, static_cast<T>(3));
+
+    const char* buffer8 = " 12345";
+    T v8 = 3;
+    auto r8 = boost::charconv::from_chars(buffer8, buffer8 + std::strlen(buffer8), v8);
+    BOOST_TEST(r8.ec == std::errc::invalid_argument);
+    BOOST_TEST_EQ(v8, static_cast<T>(3));
+
+    const char* buffer9 = "123 45";
+    T v9 = 3;
+    auto r9 = boost::charconv::from_chars(buffer9, buffer9 + std::strlen(buffer9), v9);
+    BOOST_TEST(r9);
+    BOOST_TEST_EQ(v9, static_cast<T>(123));
 }
 
 // No overflows, negative numbers, locales, etc.
diff --git a/test/from_chars_float.cpp b/test/from_chars_float.cpp
index 7da7e9f..16612ae 100644
--- a/test/from_chars_float.cpp
+++ b/test/from_chars_float.cpp
@@ -74,7 +74,7 @@ void spot_check_inf(const std::string& buffer, boost::charconv::chars_format fmt
 }
 
 template <typename T>
-void spot_check_bad_non_finite(const std::string& buffer, boost::charconv::chars_format fmt)
+void spot_check_invalid_argument(const std::string& buffer, boost::charconv::chars_format fmt)
 {
     T v = static_cast<T>(5.0L);
     auto r = boost::charconv::from_chars(buffer.c_str(), buffer.c_str() + buffer.size(), v, fmt);
@@ -1881,9 +1881,16 @@ int main()
         spot_check_nan<double>("-nan(ind)", fmt);
         spot_check_nan<long double>("-nan(ind)", fmt);
 
-        spot_check_bad_non_finite<float>("na7", fmt);
-        spot_check_bad_non_finite<float>("na", fmt);
-        spot_check_bad_non_finite<float>("in", fmt);
+        spot_check_invalid_argument<float>("na7", fmt);
+        spot_check_invalid_argument<float>("na", fmt);
+        spot_check_invalid_argument<float>("in", fmt);
+
+        spot_check_invalid_argument<float>(" 1.23", fmt);
+        spot_check_invalid_argument<float>("  1.23", fmt);
+        spot_check_invalid_argument<double>(" 1.23", fmt);
+        spot_check_invalid_argument<double>("  1.23", fmt);
+        spot_check_invalid_argument<long double>(" 1.23", fmt);
+        spot_check_invalid_argument<long double>("  1.23", fmt);
     }
 
     return boost::report_errors();