diff --git a/degesch.c b/degesch.c
index 64280c8..b15b464 100644
--- a/degesch.c
+++ b/degesch.c
@@ -952,6 +952,19 @@ buffer_goto (struct app_context *ctx, int n)
 	return false;
 }
 
+static int
+buffer_get_index (struct app_context *ctx, struct buffer *buffer)
+{
+	int index = 1;
+	LIST_FOR_EACH (struct buffer, iter, ctx->buffers)
+	{
+		if (iter == buffer)
+			return index;
+		index++;
+	}
+	return -1;
+}
+
 static void
 init_buffers (struct app_context *ctx)
 {
@@ -1291,12 +1304,8 @@ refresh_prompt (struct app_context *ctx)
 			str_append_printf (&prompt, "(%s) ", unseen_prefix);
 		free (unseen_prefix);
 
-		int buffer_index = 1;
-		for (struct buffer *iter = ctx->buffers;
-			iter && iter != buffer; iter = iter->next)
-			buffer_index++;
-
-		str_append_printf (&prompt, "%d:%s", buffer_index, buffer->name);
+		str_append_printf (&prompt, "%d:%s",
+			buffer_get_index (ctx, buffer), buffer->name);
 		if (buffer->type == BUFFER_CHANNEL && *buffer->mode)
 			str_append_printf (&prompt, "(%s)", buffer->mode);