diff --git a/src/grib_accessor_class_data_ccsds_packing.c b/src/grib_accessor_class_data_ccsds_packing.c
index 7378aabe2..7bdad0c52 100644
--- a/src/grib_accessor_class_data_ccsds_packing.c
+++ b/src/grib_accessor_class_data_ccsds_packing.c
@@ -511,7 +511,7 @@ static int pack_double(grib_accessor* a, const double* val, size_t* len)
     grib_context_log(a->context, GRIB_LOG_DEBUG,"CCSDS pack_double: packing %s, %d values", a->name, n_vals);
 
     /*ECC-1431: GRIB2: CCSDS encoding failure AEC_STREAM_ERROR*/
-    buflen = buflen * 67.0/64 + 257;
+    buflen += buflen / 20 + 256;
     buf = (unsigned char*)grib_context_buffer_malloc_clear(a->context, buflen);
 
     if (!buf) {