diff --git a/reftable/reftable-writer.h b/reftable/reftable-writer.h
index 0fbeff17f4..1e7003cd69 100644
--- a/reftable/reftable-writer.h
+++ b/reftable/reftable-writer.h
@@ -156,7 +156,7 @@ int reftable_writer_add_ref(struct reftable_writer *w,
   the records before adding them, reordering the records array passed in.
 */
 int reftable_writer_add_refs(struct reftable_writer *w,
-			     struct reftable_ref_record *refs, int n);
+			     struct reftable_ref_record *refs, size_t n);
 
 /*
   adds reftable_log_records. Log records are keyed by (refname, decreasing
@@ -171,7 +171,7 @@ int reftable_writer_add_log(struct reftable_writer *w,
   the records before adding them, reordering records array passed in.
 */
 int reftable_writer_add_logs(struct reftable_writer *w,
-			     struct reftable_log_record *logs, int n);
+			     struct reftable_log_record *logs, size_t n);
 
 /* reftable_writer_close finalizes the reftable. The writer is retained so
  * statistics can be inspected. */
diff --git a/reftable/writer.c b/reftable/writer.c
index 3b4ebdd6dc..5bad130c7e 100644
--- a/reftable/writer.c
+++ b/reftable/writer.c
@@ -395,14 +395,15 @@ out:
 }
 
 int reftable_writer_add_refs(struct reftable_writer *w,
-			     struct reftable_ref_record *refs, int n)
+			     struct reftable_ref_record *refs, size_t n)
 {
 	int err = 0;
-	int i = 0;
+
 	QSORT(refs, n, reftable_ref_record_compare_name);
-	for (i = 0; err == 0 && i < n; i++) {
+
+	for (size_t i = 0; err == 0 && i < n; i++)
 		err = reftable_writer_add_ref(w, &refs[i]);
-	}
+
 	return err;
 }
 
@@ -486,15 +487,15 @@ done:
 }
 
 int reftable_writer_add_logs(struct reftable_writer *w,
-			     struct reftable_log_record *logs, int n)
+			     struct reftable_log_record *logs, size_t n)
 {
 	int err = 0;
-	int i = 0;
+
 	QSORT(logs, n, reftable_log_record_compare_key);
 
-	for (i = 0; err == 0 && i < n; i++) {
+	for (size_t i = 0; err == 0 && i < n; i++)
 		err = reftable_writer_add_log(w, &logs[i]);
-	}
+
 	return err;
 }