diff --git a/search/search_quality/assessment_tool/assessment_tool.cpp b/search/search_quality/assessment_tool/assessment_tool.cpp
index 2df013d370..5ce4631871 100644
--- a/search/search_quality/assessment_tool/assessment_tool.cpp
+++ b/search/search_quality/assessment_tool/assessment_tool.cpp
@@ -17,6 +17,7 @@ DEFINE_string(data_path, "", "Path to data directory");
 int main(int argc, char ** argv)
 {
   search::ChangeMaxNumberOfOpenFiles(search::kMaxOpenFiles);
+  search::CheckLocale();
 
   google::SetUsageMessage("Features collector tool.");
   google::ParseCommandLineFlags(&argc, &argv, true);
diff --git a/search/search_quality/features_collector_tool/features_collector_tool.cpp b/search/search_quality/features_collector_tool/features_collector_tool.cpp
index 5d306931f4..43d3053f68 100644
--- a/search/search_quality/features_collector_tool/features_collector_tool.cpp
+++ b/search/search_quality/features_collector_tool/features_collector_tool.cpp
@@ -106,6 +106,7 @@ void DisplayStats(ostream & os, vector<Sample> const & samples, vector<Stats> co
 int main(int argc, char * argv[])
 {
   ChangeMaxNumberOfOpenFiles(kMaxOpenFiles);
+  CheckLocale();
 
   google::SetUsageMessage("Features collector tool.");
   google::ParseCommandLineFlags(&argc, &argv, true);
diff --git a/search/search_quality/helpers.cpp b/search/search_quality/helpers.cpp
index 433bf4fb1c..dc9c76e392 100644
--- a/search/search_quality/helpers.cpp
+++ b/search/search_quality/helpers.cpp
@@ -1,7 +1,12 @@
 #include "search/search_quality/helpers.hpp"
 
+#include "base/assert.hpp"
+#include "base/string_utils.hpp"
+
 #include "std/target_os.hpp"
 
+#include <memory>
+
 #include <sys/resource.h>
 
 using namespace std;
@@ -26,6 +31,38 @@ void ChangeMaxNumberOfOpenFiles(size_t n)
   setrlimit(RLIMIT_NOFILE, &rlp);
 #endif
 }
+
+void CheckLocale()
+{
+  string const kJson = "{\"coord\":123.456}";
+  string const kErrorMsg = "Bad locale. Consider setting LC_ALL=C";
+
+  double coord;
+  {
+    base::Json root(kJson.c_str());
+    FromJSONObject(root.get(), "coord", coord);
+  }
+
+  string line;
+  {
+    auto root = base::NewJSONObject();
+    ToJSONObject(*root, "coord", coord);
+
+    unique_ptr<char, JSONFreeDeleter> buffer(
+        json_dumps(root.get(), JSON_COMPACT | JSON_ENSURE_ASCII));
+
+    line.append(buffer.get());
+  }
+
+  CHECK_EQUAL(line, kJson, (kErrorMsg));
+
+  {
+    string const kTest = "123.456";
+    double value;
+    VERIFY(strings::to_double(kTest, value), (kTest));
+    CHECK_EQUAL(strings::to_string(value), kTest, (kErrorMsg));
+  }
+}
 }  // namespace search
 
 namespace m2
@@ -93,7 +130,7 @@ void ToJSONObject(json_t & root, char const * field, PointD const & point)
   json_object_set_new(&root, field, json.release());
 }
 
-bool FromJSONObjectOptional(json_t * root, std::string const & field, PointD & point)
+bool FromJSONObjectOptional(json_t * root, string const & field, PointD & point)
 {
   return FromJSONObjectOptional(root, field.c_str(), point);
 }
diff --git a/search/search_quality/helpers.hpp b/search/search_quality/helpers.hpp
index 6ea9eb9e76..9fb2707f98 100644
--- a/search/search_quality/helpers.hpp
+++ b/search/search_quality/helpers.hpp
@@ -13,6 +13,8 @@ namespace search
 size_t constexpr kMaxOpenFiles = 4000;
 
 void ChangeMaxNumberOfOpenFiles(size_t n);
+
+void CheckLocale();
 }  // namespace search
 
 namespace m2
diff --git a/search/search_quality/search_quality_tool/search_quality_tool.cpp b/search/search_quality/search_quality_tool/search_quality_tool.cpp
index 823046329b..0fde17fc1f 100644
--- a/search/search_quality/search_quality_tool/search_quality_tool.cpp
+++ b/search/search_quality/search_quality_tool/search_quality_tool.cpp
@@ -351,6 +351,7 @@ void CheckCompleteness(string const & path, m2::RectD const & viewport, DataSour
 int main(int argc, char * argv[])
 {
   ChangeMaxNumberOfOpenFiles(kMaxOpenFiles);
+  CheckLocale();
 
   ios_base::sync_with_stdio(false);
   Platform & platform = GetPlatform();