diff --git a/actions/actiontsc.h b/actions/actiontsc.h
index 0aa5c15..0c951f1 100644
--- a/actions/actiontsc.h
+++ b/actions/actiontsc.h
@@ -50,12 +50,12 @@ template<class D> MString ActionTSC::DoAction(const CLArgs& args, D& ds)
  if(!data) return "Can't read data";
  if(!data.Unit().Exist()) michlib::errmessage("Unknown measurement unit!");
 
- MString outfmt = args.contains("format") ? args.at("format") : "bin";
+ MString name   = args.contains("out") ? args.at("out") : "out.bin";
+ MString outfmt = args.contains("format") ? args.at("format") : (GetExt(name) == "nc" ? "nc" : "bin");
 
  if(outfmt == "bin")
  {
-  BFileW  fw;
-  MString name = args.contains("out") ? args.at("out") : "out.bin";
+  BFileW fw;
 
   fw.Create(name, 3);
   fw.SetColumnName(1, "Longitude");
@@ -75,7 +75,6 @@ template<class D> MString ActionTSC::DoAction(const CLArgs& args, D& ds)
 
  if(outfmt == "nc" || outfmt == "netcdf")
  {
-  MString name = args.contains("out") ? args.at("out") : "out.nc";
   int     ret;
   int     ncid, dimid, dimidxy[2];
   int     lonid, latid, vid;
diff --git a/include/ParseArgs.h b/include/ParseArgs.h
index 0932c88..d286093 100644
--- a/include/ParseArgs.h
+++ b/include/ParseArgs.h
@@ -6,3 +6,4 @@ using michlib::SList;
 using CLArgs = std::map<MString, MString>;
 
 CLArgs ParseArgs(int argc, char** argv);
+MString GetExt(const MString& fname);
diff --git a/src/ParseArgs.cpp b/src/ParseArgs.cpp
index 05dc4b1..5bbe757 100644
--- a/src/ParseArgs.cpp
+++ b/src/ParseArgs.cpp
@@ -33,3 +33,10 @@ CLArgs ParseArgs(int argc, char** argv)
 
  return out;
 }
+
+MString GetExt(const MString& fname)
+{
+ for(size_t i = fname.Len(); i != 0; i--)
+  if(fname[i - 1] == '.') return fname.SubStr(i + 1, fname.Len() - i);
+ return "";
+}