diff --git a/src/libcode/vx_grid/tcrmw_grid.cc b/src/libcode/vx_grid/tcrmw_grid.cc
index 991842e7a0..a2e1738e1b 100644
--- a/src/libcode/vx_grid/tcrmw_grid.cc
+++ b/src/libcode/vx_grid/tcrmw_grid.cc
@@ -425,7 +425,7 @@ RotatedLatLonGrid::latlon_to_xy(true_lat, true_lon, x, y);
 
 x -= Nx*floor(x/Nx);
 
-y -= Ny*floor(y/Ny);
+x -= Nx*floor(x/Nx);
 
 
 return;
@@ -442,7 +442,7 @@ void TcrmwGrid::xy_to_latlon(double x, double y, double & true_lat, double & tru
 
 x -= Nx*floor(x/Nx);
 
-y -= Ny*floor(y/Ny);
+x -= Nx*floor(x/Nx);
 
 RotatedLatLonGrid::xy_to_latlon(x, y, true_lat, true_lon);