diff --git a/include/boost/histogram/axis.hpp b/include/boost/histogram/axis.hpp
index b568f711..f4183478 100644
--- a/include/boost/histogram/axis.hpp
+++ b/include/boost/histogram/axis.hpp
@@ -122,10 +122,7 @@ public:
   inline int index(double x) const 
   {
     const double z = (x - min_) / delta_;
-    const int i = static_cast<int>(z);
-    if (i > bins())
-      return bins();
-    return z >= 0.0 ? i : -1;
+    return z < 0.0 ? -1 : (z > bins() ? bins() : static_cast<int>(z));
   }
 
   double operator[](int idx) const
diff --git a/test/axis_test.cpp b/test/axis_test.cpp
index f26529b4..b2e4ae46 100644
--- a/test/axis_test.cpp
+++ b/test/axis_test.cpp
@@ -32,6 +32,8 @@ BOOST_AUTO_TEST_CASE(regular_axis_operators) {
     BOOST_CHECK_EQUAL(a.index(0.99), 2);
     BOOST_CHECK_EQUAL(a.index(1.0), 3);
     BOOST_CHECK_EQUAL(a.index(10.), 3);
+    BOOST_CHECK_EQUAL(a.index(std::numeric_limits<double>::infinity()), 3);
+    BOOST_CHECK_EQUAL(a.index(-std::numeric_limits<double>::infinity()), -1);
 }
 
 BOOST_AUTO_TEST_CASE(polar_axis_operators) {