diff --git a/internal/ackhandler/sent_packet_handler.go b/internal/ackhandler/sent_packet_handler.go
index d542e99f..7d997ead 100644
--- a/internal/ackhandler/sent_packet_handler.go
+++ b/internal/ackhandler/sent_packet_handler.go
@@ -114,6 +114,9 @@ func (h *sentPacketHandler) SetHandshakeComplete() {
 	for _, pnSpace := range []*packetNumberSpace{h.initialPackets, h.handshakePackets} {
 		var cryptoPackets []*Packet
 		pnSpace.history.Iterate(func(p *Packet) (bool, error) {
+			if p.includedInBytesInFlight {
+				h.bytesInFlight -= p.Length
+			}
 			cryptoPackets = append(cryptoPackets, p)
 			return true, nil
 		})
diff --git a/internal/ackhandler/sent_packet_handler_test.go b/internal/ackhandler/sent_packet_handler_test.go
index 1697691e..efc20890 100644
--- a/internal/ackhandler/sent_packet_handler_test.go
+++ b/internal/ackhandler/sent_packet_handler_test.go
@@ -860,11 +860,13 @@ var _ = Describe("SentPacketHandler", func() {
 				p := ackElicitingPacket(&Packet{PacketNumber: i, EncryptionLevel: protocol.EncryptionHandshake})
 				handler.SentPacket(p)
 			}
+			Expect(handler.bytesInFlight).ToNot(BeZero())
 			handler.queuePacketForRetransmission(getPacket(1, protocol.EncryptionInitial), handler.getPacketNumberSpace(protocol.EncryptionInitial))
 			handler.queuePacketForRetransmission(getPacket(3, protocol.EncryptionHandshake), handler.getPacketNumberSpace(protocol.EncryptionHandshake))
 			handler.SetHandshakeComplete()
 			Expect(handler.initialPackets.history.Len()).To(BeZero())
 			Expect(handler.handshakePackets.history.Len()).To(BeZero())
+			Expect(handler.bytesInFlight).To(BeZero())
 			packet := handler.DequeuePacketForRetransmission()
 			Expect(packet).To(BeNil())
 		})