diff --git a/chunks/chunks.go b/chunks/chunks.go
index 5eab2398..569aeddc 100644
--- a/chunks/chunks.go
+++ b/chunks/chunks.go
@@ -205,6 +205,7 @@ func (w *Writer) WriteChunks(chks ...Meta) error {
 	for _, c := range chks {
 		maxLen += binary.MaxVarintLen32 + 1 // The number of bytes in the chunk and its encoding.
 		maxLen += int64(len(c.Chunk.Bytes()))
+		maxLen += 4 // The 4 bytes of crc32
 	}
 	newsz := w.n + maxLen