diff --git a/src/restic/fuse/blob_size_cache.go b/src/restic/fuse/blob_size_cache.go
index d74bfe8be..b33a8e983 100644
--- a/src/restic/fuse/blob_size_cache.go
+++ b/src/restic/fuse/blob_size_cache.go
@@ -15,7 +15,7 @@ type BlobSizeCache struct {
 func NewBlobSizeCache(ctx context.Context, idx restic.Index) *BlobSizeCache {
 	m := make(map[restic.ID]uint, 1000)
 	for pb := range idx.Each(ctx) {
-		m[pb.ID] = pb.Length
+		m[pb.ID] = uint(restic.PlaintextLength(int(pb.Length)))
 	}
 	return &BlobSizeCache{
 		m: m,