diff --git a/message.go b/message.go
index c320006ba..0539e6038 100644
--- a/message.go
+++ b/message.go
@@ -49,6 +49,17 @@ func (msg *Message) size() int32 {
 	return 4 + 1 + 1 + sizeofBytes(msg.Key) + sizeofBytes(msg.Value) + timestampSize
 }
 
+func (msg *Message) headerSize() int {
+	return varArrayLen(len(msg.Headers), func(i int) int {
+		h := &msg.Headers[i]
+		return varStringLen(h.Key) + varBytesLen(h.Value)
+	})
+}
+
+func (msg *Message) totalSize() int32 {
+	return int32(msg.headerSize()) + msg.size()
+}
+
 type message struct {
 	CRC        int32
 	MagicByte  int8
diff --git a/writer.go b/writer.go
index f5d6fc2c5..1d4ccbab3 100644
--- a/writer.go
+++ b/writer.go
@@ -1216,7 +1216,7 @@ func newWriteBatch(now time.Time, timeout time.Duration) *writeBatch {
 }
 
 func (b *writeBatch) add(msg Message, maxSize int, maxBytes int64) bool {
-	bytes := int64(msg.size())
+	bytes := int64(msg.totalSize())
 
 	if b.size > 0 && (b.bytes+bytes) > maxBytes {
 		return false