diff --git a/UI/window-basic-filters.cpp b/UI/window-basic-filters.cpp
index 58ee308fe..a685cb59a 100644
--- a/UI/window-basic-filters.cpp
+++ b/UI/window-basic-filters.cpp
@@ -1281,7 +1281,7 @@ void OBSBasicFilters::FiltersMoved(const QModelIndex &, int srcIdxStart, int,
 		neighborIdx = 0;
 
 	OBSSource neighbor = GetFilter(neighborIdx, isAsync);
-	size_t idx = obs_source_filter_get_index(source, neighbor);
+	int idx = obs_source_filter_get_index(source, neighbor);
 
 	OBSSource filter = GetFilter(list->currentRow(), isAsync);
 	obs_source_filter_set_index(source, filter, idx);
diff --git a/libobs/obs-source.c b/libobs/obs-source.c
index 9c7ec853c..a54f09e32 100644
--- a/libobs/obs-source.c
+++ b/libobs/obs-source.c
@@ -3294,12 +3294,12 @@ void obs_source_filter_set_order(obs_source_t *source, obs_source_t *filter,
 		obs_source_dosignal(source, NULL, "reorder_filters");
 }
 
-size_t obs_source_filter_get_index(obs_source_t *source, obs_source_t *filter)
+int obs_source_filter_get_index(obs_source_t *source, obs_source_t *filter)
 {
 	if (!obs_source_valid(source, "obs_source_filter_get_index"))
-		return DARRAY_INVALID;
+		return -1;
 	if (!obs_ptr_valid(filter, "obs_source_filter_get_index"))
-		return DARRAY_INVALID;
+		return -1;
 
 	size_t idx;
 
@@ -3307,7 +3307,7 @@ size_t obs_source_filter_get_index(obs_source_t *source, obs_source_t *filter)
 	idx = da_find(source->filters, &filter, 0);
 	pthread_mutex_unlock(&source->filter_mutex);
 
-	return idx;
+	return idx != DARRAY_INVALID ? (int)idx : -1;
 }
 
 static bool set_filter_index(obs_source_t *source, obs_source_t *filter,
diff --git a/libobs/obs.h b/libobs/obs.h
index 56d397bb6..93948a7d6 100644
--- a/libobs/obs.h
+++ b/libobs/obs.h
@@ -1134,8 +1134,8 @@ EXPORT void obs_source_filter_set_order(obs_source_t *source,
 					enum obs_order_movement movement);
 
 /** Gets filter index */
-EXPORT size_t obs_source_filter_get_index(obs_source_t *source,
-					  obs_source_t *filter);
+EXPORT int obs_source_filter_get_index(obs_source_t *source,
+				       obs_source_t *filter);
 
 /** Sets filter index */
 EXPORT void obs_source_filter_set_index(obs_source_t *source,