diff --git a/lib/protocol/metrics.go b/lib/protocol/metrics.go
index b1ea6281c..954597abd 100644
--- a/lib/protocol/metrics.go
+++ b/lib/protocol/metrics.go
@@ -37,6 +37,12 @@ var (
 		Name:      "recv_bytes_total",
 		Help:      "Total amount of data received",
 	}, []string{"device"})
+	metricDeviceRecvDecompressedBytes = promauto.NewCounterVec(prometheus.CounterOpts{
+		Namespace: "syncthing",
+		Subsystem: "protocol",
+		Name:      "recv_decompressed_bytes_total",
+		Help:      "Total amount of data received, after decompression",
+	}, []string{"device"})
 	metricDeviceRecvMessages = promauto.NewCounterVec(prometheus.CounterOpts{
 		Namespace: "syncthing",
 		Subsystem: "protocol",
diff --git a/lib/protocol/protocol.go b/lib/protocol/protocol.go
index ab14c9884..7a40a72ee 100644
--- a/lib/protocol/protocol.go
+++ b/lib/protocol/protocol.go
@@ -541,6 +541,8 @@ func (c *rawConnection) readMessageAfterHeader(hdr Header, fourByteBuf []byte) (
 
 	// ... and is then unmarshalled
 
+	metricDeviceRecvDecompressedBytes.WithLabelValues(c.idString).Add(float64(4 + len(buf)))
+
 	msg, err := newMessage(hdr.Type)
 	if err != nil {
 		BufferPool.Put(buf)
@@ -581,6 +583,8 @@ func (c *rawConnection) readHeader(fourByteBuf []byte) (Header, error) {
 		return Header{}, fmt.Errorf("unmarshalling header: %w", err)
 	}
 
+	metricDeviceRecvDecompressedBytes.WithLabelValues(c.idString).Add(float64(2 + len(buf)))
+
 	return hdr, nil
 }