diff --git a/src/vm/wren_vm.c b/src/vm/wren_vm.c
index ab2f3406..7471bf59 100644
--- a/src/vm/wren_vm.c
+++ b/src/vm/wren_vm.c
@@ -188,12 +188,12 @@ void wrenCollectGarbage(WrenVM* vm)
   double elapsed = ((double)clock() / CLOCKS_PER_SEC) - startTime;
   // Explicit cast because size_t has different sizes on 32-bit and 64-bit and
   // we need a consistent type for the format string.
-  printf("GC %lu before, %lu after (%lu collected), next at %lu. Took %.3fs.\n",
+  printf("GC %lu before, %lu after (%lu collected), next at %lu. Took %.3fms.\n",
          (unsigned long)before,
          (unsigned long)vm->bytesAllocated,
          (unsigned long)(before - vm->bytesAllocated),
          (unsigned long)vm->nextGC,
-         elapsed);
+         elapsed*1000.0);
 #endif
 }