diff --git a/src/gmt_gdalcall.c b/src/gmt_gdalcall.c
index f677d534e7c..6a6f729b984 100644
--- a/src/gmt_gdalcall.c
+++ b/src/gmt_gdalcall.c
@@ -184,7 +184,7 @@ GMT_LOCAL int save_grid_with_GMT(struct GMT_CTRL *GMT, GDALDatasetH hDstDS, stru
 	GDALRasterBandH	hBand;
 
 	hBand = GDALGetRasterBand(hDstDS, 1);
-	nPixelSize = GDALGetDataTypeSize(GDALGetRasterDataType(hBand)) / 8;	/* /8 because return value is in BITS */
+	nPixelSize = GDALGetDataTypeSizeBytes(GDALGetRasterDataType(hBand));
 	nXSize = GDALGetRasterXSize(hDstDS);
 	nYSize = GDALGetRasterYSize(hDstDS);
 
diff --git a/src/gmt_gdalread.c b/src/gmt_gdalread.c
index 5561c7f683a..6ca09d1f534 100644
--- a/src/gmt_gdalread.c
+++ b/src/gmt_gdalread.c
@@ -1041,7 +1041,7 @@ int gmt_gdalread (struct GMT_CTRL *GMT, char *gdal_filename, struct GMT_GDALREAD
 
 	/* The following assumes that all bands have the same PixelSize, data type. Otherwise ... */
 	hBand = GDALGetRasterBand(hDataset, first_layer);
-	nPixelSize = GDALGetDataTypeSize(GDALGetRasterDataType(hBand)) / 8;	/* /8 because return value is in BITS */
+	nPixelSize = GDALGetDataTypeSizeBytes(GDALGetRasterDataType(hBand));
 
 	if (jump) {
 		nBufXSize[0] = XDim / jump;