diff --git a/include/protozero/iterators.hpp b/include/protozero/iterators.hpp
index 0f44c465..7a1bc433 100644
--- a/include/protozero/iterators.hpp
+++ b/include/protozero/iterators.hpp
@@ -243,30 +243,30 @@ class const_fixed_iterator {
     }
 
     const_fixed_iterator& operator+=(difference_type val) noexcept {
-        m_data += (sizeof(value_type) * val);
+        m_data += (static_cast<difference_type>(sizeof(value_type)) * val);
         return *this;
     }
 
     friend const_fixed_iterator operator+(const_fixed_iterator lhs, difference_type rhs) noexcept {
         const_fixed_iterator tmp{lhs};
-        tmp.m_data += (sizeof(value_type) * rhs);
+        tmp.m_data += (static_cast<difference_type>(sizeof(value_type)) * rhs);
         return tmp;
     }
 
     friend const_fixed_iterator operator+(difference_type lhs, const_fixed_iterator rhs) noexcept {
         const_fixed_iterator tmp{rhs};
-        tmp.m_data += (sizeof(value_type) * lhs);
+        tmp.m_data += (static_cast<difference_type>(sizeof(value_type)) * lhs);
         return tmp;
     }
 
     const_fixed_iterator& operator-=(difference_type val) noexcept {
-        m_data -= (sizeof(value_type) * val);
+        m_data -= (static_cast<difference_type>(sizeof(value_type)) * val);
         return *this;
     }
 
     friend const_fixed_iterator operator-(const_fixed_iterator lhs, difference_type rhs) noexcept {
         const_fixed_iterator tmp{lhs};
-        tmp.m_data -= (sizeof(value_type) * rhs);
+        tmp.m_data -= (static_cast<difference_type>(sizeof(value_type)) * rhs);
         return tmp;
     }
 
diff --git a/test/unit/test_iterators.cpp b/test/unit/test_iterators.cpp
index db00a9fb..9a33531a 100644
--- a/test/unit/test_iterators.cpp
+++ b/test/unit/test_iterators.cpp
@@ -40,3 +40,31 @@ TEST_CASE("get_packed varint rejects a truncated trailing varint") {
     REQUIRE_THROWS_AS(item.get_packed_uint64(), protozero::end_of_buffer_exception);
 }
 
+
+TEST_CASE("fixed_iterator supports negative offsets") {
+    // field 1, wire type 2; length 12; fixed32 values 1, 2 and 3.
+    const std::string buffer{"\x0a\x0c\x01\x00\x00\x00\x02\x00\x00\x00\x03\x00\x00\x00", 14};
+    protozero::pbf_reader item{buffer};
+
+    REQUIRE(item.next());
+    const auto range = item.get_packed_fixed32();
+    const auto end = range.end();
+
+    REQUIRE(*std::prev(end) == 3);
+    REQUIRE(end[-1] == 3);
+    REQUIRE(end[-3] == 1);
+    REQUIRE(*(end + -2) == 2);
+    REQUIRE(*(-2 + end) == 2);
+    REQUIRE(*(end - 2) == 2);
+    REQUIRE(*(range.begin() - -1) == 2);
+
+    auto it = end;
+    it += -1;
+    REQUIRE(*it == 3);
+    it -= 1;
+    REQUIRE(*it == 2);
+    it -= -1;
+    REQUIRE(*it == 3);
+    REQUIRE(it - end == -1);
+    REQUIRE(range.begin() - end == -3);
+}