diff --git a/src/vecs2mmap.c b/src/vecs2mmap.c
new file mode 100644
index 0000000..3d72355
--- /dev/null
+++ b/src/vecs2mmap.c
@@ -0,0 +1,29 @@
+/* Writes the memory mappable form of an already trained model, so that
+ * derekovecs does not have to build it itself on its first start. dereko2vec
+ * does this right after training, this tool is for models that were trained
+ * before, or whose converted files were lost.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "mmap_vecs.h"
+
+int main(int argc, char **argv) {
+  int i;
+
+  if (argc < 2 || strcmp(argv[1], "-h") == 0) {
+    printf("usage: %s <model.vecs> [<model.vecs> ...]\n\n"
+           "Writes <model.vecs>.vecs and <model.vecs>.words, the memory\n"
+           "mappable form derekovecs uses.\n", argv[0]);
+    return argc < 2 ? 1 : 0;
+  }
+
+  for (i = 1; i < argc; i++) {
+    printf("Converting %s to memory mappable structures\n", argv[i]);
+    fflush(stdout);
+    if (convert_vecs_to_mmap(argv[i]) != 0)
+      return 1;
+  }
+  return 0;
+}