diff --git a/base/string_utils.cpp b/base/string_utils.cpp
index 2263af3255..f37e88bcd9 100644
--- a/base/string_utils.cpp
+++ b/base/string_utils.cpp
@@ -1,6 +1,8 @@
-#include "base/assert.hpp"
 #include "base/string_utils.hpp"
 
+#include "base/assert.hpp"
+#include "base/checked_cast.hpp"
+
 #include "std/target_os.hpp"
 
 #include <algorithm>
@@ -103,6 +105,16 @@ bool to_int64(char const * s, int64_t & i)
   return *stop == 0 && s != stop;
 }
 
+bool to_size_t(char const * s, size_t & i, int base)
+{
+  uint64_t num = 0;
+  if (!to_uint64(s, num, base))
+    return false;
+
+  i = static_cast<size_t>(num);
+  return i == num;
+}
+
 bool to_float(char const * s, float & f)
 {
   char * stop;
diff --git a/base/string_utils.hpp b/base/string_utils.hpp
index 1f86537a4b..43cc707fee 100644
--- a/base/string_utils.hpp
+++ b/base/string_utils.hpp
@@ -376,6 +376,7 @@ WARN_UNUSED_RESULT bool to_int(char const * s, int & i, int base = 10);
 WARN_UNUSED_RESULT bool to_uint(char const * s, unsigned int & i, int base = 10);
 WARN_UNUSED_RESULT bool to_uint64(char const * s, uint64_t & i, int base = 10);
 WARN_UNUSED_RESULT bool to_int64(char const * s, int64_t & i);
+WARN_UNUSED_RESULT bool to_size_t(char const * s, size_t & i, int base = 10);
 WARN_UNUSED_RESULT bool to_float(char const * s, float & f);
 WARN_UNUSED_RESULT bool to_double(char const * s, double & d);
 
@@ -402,6 +403,10 @@ WARN_UNUSED_RESULT inline bool to_int64(std::string const & s, int64_t & i)
 {
   return to_int64(s.c_str(), i);
 }
+WARN_UNUSED_RESULT inline bool to_size_t(std::string const & s, size_t & i)
+{
+  return to_size_t(s.c_str(), i);
+}
 WARN_UNUSED_RESULT inline bool to_float(std::string const & s, float & f)
 {
   return to_float(s.c_str(), f);