diff --git a/cmd_stream.go b/cmd_stream.go
index b6d0034..e8d9b4d 100644
--- a/cmd_stream.go
+++ b/cmd_stream.go
@@ -569,9 +569,11 @@ func (m *Miniredis) cmdXinfoStream(c *server.Peer, args []string) {
 			return
 		}
 
-		c.WriteMapLen(1)
+		c.WriteMapLen(2)
 		c.WriteBulk("length")
 		c.WriteInt(len(s.entries))
+		c.WriteBulk("entries-added")
+		c.WriteInt(s.entriesAdded)
 	})
 }
 
@@ -610,9 +612,14 @@ func (m *Miniredis) cmdXinfoGroups(c *server.Peer, args []string) {
 			c.WriteBulk("last-delivered-id")
 			c.WriteBulk(g.lastID)
 			c.WriteBulk("entries-read")
-			c.WriteNull()
+			c.WriteInt(g.entriesRead)
 			c.WriteBulk("lag")
-			c.WriteInt(len(g.stream.entries))
+			lag := g.lag()
+			if lag == -1 {
+				c.WriteNull()
+			} else {
+				c.WriteInt(lag)
+			}
 		}
 	})
 }
diff --git a/cmd_stream_test.go b/cmd_stream_test.go
index 719a28e..9dea28e 100644
--- a/cmd_stream_test.go
+++ b/cmd_stream_test.go
@@ -35,7 +35,7 @@ func TestStream(t *testing.T) {
 
 	mustDo(t, c,
 		"XINFO", "STREAM", "s",
-		proto.Array(proto.String("length"), proto.Int(1)),
+		proto.Array(proto.String("length"), proto.Int(1), proto.String("entries-added"), proto.Int(1)),
 	)
 
 	now := time.Date(2001, 1, 1, 4, 4, 5, 4000000, time.UTC)
@@ -73,7 +73,7 @@ func TestStream(t *testing.T) {
 	t.Run("resp3", func(t *testing.T) {
 		mustDo(t, c,
 			"XINFO", "STREAM", "s",
-			proto.Map(proto.String("length"), proto.Int(1)),
+			proto.Map(proto.String("length"), proto.Int(1), proto.String("entries-added"), proto.Int(1)),
 		)
 	})
 }
@@ -546,7 +546,7 @@ func TestStreamInfo(t *testing.T) {
 
 	mustDo(t, c,
 		"XINFO", "STREAM", "planets",
-		proto.Array(proto.String("length"), proto.Int(1)),
+		proto.Array(proto.String("length"), proto.Int(1), proto.String("entries-added"), proto.Int(1)),
 	)
 
 	mustDo(t, c,
@@ -605,7 +605,7 @@ func TestStreamGroup(t *testing.T) {
 				proto.String("consumers"), proto.Int(0),
 				proto.String("pending"), proto.Int(0),
 				proto.String("last-delivered-id"), proto.String("0-0"),
-				proto.String("entries-read"), proto.Nil,
+				proto.String("entries-read"), proto.Int(0),
 				proto.String("lag"), proto.Int(0),
 			),
 		),
@@ -627,7 +627,7 @@ func TestStreamGroup(t *testing.T) {
 				proto.String("consumers"), proto.Int(1),
 				proto.String("pending"), proto.Int(0),
 				proto.String("last-delivered-id"), proto.String("0-0"),
-				proto.String("entries-read"), proto.Nil,
+				proto.String("entries-read"), proto.Int(0),
 				proto.String("lag"), proto.Int(0),
 			),
 		),
@@ -660,7 +660,7 @@ func TestStreamGroup(t *testing.T) {
 				proto.String("consumers"), proto.Int(0),
 				proto.String("pending"), proto.Int(0),
 				proto.String("last-delivered-id"), proto.String("0-0"),
-				proto.String("entries-read"), proto.Nil,
+				proto.String("entries-read"), proto.Int(0),
 				proto.String("lag"), proto.Int(0),
 			),
 		),
@@ -727,7 +727,7 @@ func TestStreamReadGroup(t *testing.T) {
 				proto.String("consumers"), proto.Int(0),
 				proto.String("pending"), proto.Int(0),
 				proto.String("last-delivered-id"), proto.String("0-0"),
-				proto.String("entries-read"), proto.Nil,
+				proto.String("entries-read"), proto.Int(0),
 				proto.String("lag"), proto.Int(0),
 			),
 		),
@@ -747,6 +747,20 @@ func TestStreamReadGroup(t *testing.T) {
 		"XLEN", "planets",
 	)
 
+	mustDo(t, c,
+		"XINFO", "GROUPS", "planets",
+		proto.Array(
+			proto.Array(
+				proto.String("name"), proto.String("processing"),
+				proto.String("consumers"), proto.Int(0),
+				proto.String("pending"), proto.Int(0),
+				proto.String("last-delivered-id"), proto.String("0-0"),
+				proto.String("entries-read"), proto.Int(0),
+				proto.String("lag"), proto.Int(1),
+			),
+		),
+	)
+
 	mustDo(t, c,
 		"XREADGROUP", "GROUP", "processing", "alice", "STREAMS", "planets", ">",
 		proto.Array(
@@ -762,8 +776,8 @@ func TestStreamReadGroup(t *testing.T) {
 				proto.String("consumers"), proto.Int(1),
 				proto.String("pending"), proto.Int(1),
 				proto.String("last-delivered-id"), proto.String("0-1"),
-				proto.String("entries-read"), proto.Nil,
-				proto.String("lag"), proto.Int(1),
+				proto.String("entries-read"), proto.Int(1),
+				proto.String("lag"), proto.Int(0),
 			),
 		),
 	)
@@ -806,6 +820,11 @@ func TestStreamDelete(t *testing.T) {
 		proto.String("0-1"),
 	)
 
+	mustDo(t, c,
+		"XADD", "planets", "0-2", "name", "Venus",
+		proto.String("0-2"),
+	)
+
 	mustDo(t, c,
 		"XREADGROUP", "GROUP", "processing", "alice", "STREAMS", "planets", ">",
 		proto.Array(
@@ -816,24 +835,84 @@ func TestStreamDelete(t *testing.T) {
 						proto.String("0-1"),
 						proto.Strings("name", "Mercury"),
 					),
+					proto.Array(
+						proto.String("0-2"),
+						proto.Strings("name", "Venus"),
+					),
 				),
 			),
 		),
 	)
 
 	mustDo(t, c,
-		"XADD", "planets", "0-2", "name", "Mercury",
-		proto.String("0-2"),
+		"XINFO", "GROUPS", "planets",
+		proto.Array(
+			proto.Array(
+				proto.String("name"), proto.String("processing"),
+				proto.String("consumers"), proto.Int(1),
+				proto.String("pending"), proto.Int(2),
+				proto.String("last-delivered-id"), proto.String("0-2"),
+				proto.String("entries-read"), proto.Int(2),
+				proto.String("lag"), proto.Int(0),
+			),
+		),
+	)
+
+	mustDo(t, c,
+		"XADD", "planets", "0-3", "name", "Earth",
+		proto.String("0-3"),
+	)
+
+	mustDo(t, c,
+		"XINFO", "GROUPS", "planets",
+		proto.Array(
+			proto.Array(
+				proto.String("name"), proto.String("processing"),
+				proto.String("consumers"), proto.Int(1),
+				proto.String("pending"), proto.Int(2),
+				proto.String("last-delivered-id"), proto.String("0-2"),
+				proto.String("entries-read"), proto.Int(2),
+				proto.String("lag"), proto.Int(1),
+			),
+		),
 	)
 
 	must1(t, c,
 		"XDEL", "planets", "0-1",
 	)
 
+	mustDo(t, c,
+		"XINFO", "GROUPS", "planets",
+		proto.Array(
+			proto.Array(
+				proto.String("name"), proto.String("processing"),
+				proto.String("consumers"), proto.Int(1),
+				proto.String("pending"), proto.Int(1),
+				proto.String("last-delivered-id"), proto.String("0-2"),
+				proto.String("entries-read"), proto.Int(2),
+				proto.String("lag"), proto.Int(1),
+			),
+		),
+	)
+
 	must1(t, c,
 		"XDEL", "planets", "0-2",
 	)
 
+	mustDo(t, c,
+		"XINFO", "GROUPS", "planets",
+		proto.Array(
+			proto.Array(
+				proto.String("name"), proto.String("processing"),
+				proto.String("consumers"), proto.Int(1),
+				proto.String("pending"), proto.Int(0),
+				proto.String("last-delivered-id"), proto.String("0-2"),
+				proto.String("entries-read"), proto.Int(2),
+				proto.String("lag"), proto.Nil,
+			),
+		),
+	)
+
 	mustDo(t, c,
 		"XREADGROUP", "GROUP", "processing", "alice", "STREAMS", "planets", "0-0",
 		proto.Array(
@@ -865,9 +944,38 @@ func TestStreamAck(t *testing.T) {
 		),
 	)
 
+	mustDo(t, c,
+		"XINFO", "GROUPS", "planets",
+		proto.Array(
+			proto.Array(
+				proto.String("name"), proto.String("processing"),
+				proto.String("consumers"), proto.Int(1),
+				proto.String("pending"), proto.Int(1),
+				proto.String("last-delivered-id"), proto.String("0-1"),
+				proto.String("entries-read"), proto.Int(1),
+				proto.String("lag"), proto.Int(0),
+			),
+		),
+	)
+
 	must1(t, c,
 		"XACK", "planets", "processing", "0-1",
 	)
+
+	mustDo(t, c,
+		"XINFO", "GROUPS", "planets",
+		proto.Array(
+			proto.Array(
+				proto.String("name"), proto.String("processing"),
+				proto.String("consumers"), proto.Int(1),
+				proto.String("pending"), proto.Int(0),
+				proto.String("last-delivered-id"), proto.String("0-1"),
+				proto.String("entries-read"), proto.Int(1),
+				proto.String("lag"), proto.Int(0),
+			),
+		),
+	)
+
 	mustDo(t, c,
 		"XREADGROUP", "GROUP", "processing", "alice", "STREAMS", "planets", "0-0",
 		proto.Array(
@@ -885,8 +993,8 @@ func TestStreamAck(t *testing.T) {
 				proto.String("consumers"), proto.Int(1),
 				proto.String("pending"), proto.Int(0),
 				proto.String("last-delivered-id"), proto.String("0-1"),
-				proto.String("entries-read"), proto.Nil,
-				proto.String("lag"), proto.Int(1),
+				proto.String("entries-read"), proto.Int(1),
+				proto.String("lag"), proto.Int(0),
 			),
 		),
 	)
@@ -1353,8 +1461,8 @@ func TestStreamAutoClaim(t *testing.T) {
 				proto.String("consumers"), proto.Int(0),
 				proto.String("pending"), proto.Int(0),
 				proto.String("last-delivered-id"), proto.String("0-2"),
-				proto.String("entries-read"), proto.Nil,
-				proto.String("lag"), proto.Int(2),
+				proto.String("entries-read"), proto.Int(2),
+				proto.String("lag"), proto.Int(0),
 			),
 		),
 	)
@@ -1428,7 +1536,7 @@ func TestStreamClaim(t *testing.T) {
 				proto.String("consumers"), proto.Int(1),
 				proto.String("pending"), proto.Int(2),
 				proto.String("last-delivered-id"), proto.String("0-0"),
-				proto.String("entries-read"), proto.Nil,
+				proto.String("entries-read"), proto.Int(0),
 				proto.String("lag"), proto.Int(2),
 			),
 		),
@@ -1479,8 +1587,8 @@ func TestStreamClaim(t *testing.T) {
 				proto.String("consumers"), proto.Int(2),
 				proto.String("pending"), proto.Int(1),
 				proto.String("last-delivered-id"), proto.String("0-0"),
-				proto.String("entries-read"), proto.Nil,
-				proto.String("lag"), proto.Int(1),
+				proto.String("entries-read"), proto.Int(0),
+				proto.String("lag"), proto.Int(2),
 			),
 		),
 	)
diff --git a/stream.go b/stream.go
index 55faa5e..8ec81c6 100644
--- a/stream.go
+++ b/stream.go
@@ -18,6 +18,7 @@ type streamKey struct {
 	entries         []StreamEntry
 	groups          map[string]*streamGroup
 	lastAllocatedID string
+	entriesAdded    int
 	mu              sync.Mutex
 }
 
@@ -30,10 +31,12 @@ type StreamEntry struct {
 }
 
 type streamGroup struct {
-	stream    *streamKey
-	lastID    string
-	pending   []pendingEntry
-	consumers map[string]*consumer
+	stream           *streamKey
+	lastID           string
+	pending          []pendingEntry
+	consumers        map[string]*consumer
+	entriesRead      int
+	entriesReadValid bool
 }
 
 type consumer struct {
@@ -93,6 +96,14 @@ func (s *streamKey) lastIDUnlocked() string {
 	return s.entries[len(s.entries)-1].ID
 }
 
+func (s *streamKey) firstIDUnlocked() string {
+	if len(s.entries) == 0 {
+		return "0-0"
+	}
+
+	return s.entries[0].ID
+}
+
 func (s *streamKey) copy() *streamKey {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -218,13 +229,22 @@ func (s *streamKey) createGroup(group, id string) error {
 		return errors.New("BUSYGROUP Consumer Group name already exists")
 	}
 
+	var entriesRead = 0
+	var entriesReadValid = true
 	if id == "$" {
 		id = s.lastIDUnlocked()
+		entriesRead = len(s.entries)
+	} else if id == "0" || id == "0-0" || id == s.firstIDUnlocked() {
+		entriesRead = 0
+	} else {
+		entriesReadValid = false
 	}
 	s.groups[group] = &streamGroup{
-		stream:    s,
-		lastID:    id,
-		consumers: map[string]*consumer{},
+		stream:           s,
+		lastID:           id,
+		consumers:        map[string]*consumer{},
+		entriesRead:      entriesRead,
+		entriesReadValid: entriesReadValid,
 	}
 	return nil
 }
@@ -255,6 +275,7 @@ func (s *streamKey) add(entryID string, values []string, now time.Time) (string,
 		ID:     entryID,
 		Values: values,
 	})
+	s.entriesAdded++
 	return entryID, nil
 }
 
@@ -263,10 +284,26 @@ func (s *streamKey) trim(n int) {
 	defer s.mu.Unlock()
 
 	if len(s.entries) > n {
+		for _, group := range s.groups {
+			for _, entry := range s.entries[:n] {
+				group.onDelete(entry.ID)
+			}
+		}
 		s.entries = s.entries[len(s.entries)-n:]
 	}
 }
 
+func (g *streamGroup) onDelete(id string) {
+	if !g.entriesReadValid {
+		return
+	}
+	compare := streamCmp(g.lastID, id)
+	if compare <= 0 {
+		// an item between last-delivered-id and last-written-id is deleted. Entries read is not valid anymore
+		g.entriesReadValid = false
+	}
+}
+
 // trimBefore deletes entries with an id less than the provided id
 // and returns the number of entries deleted
 func (s *streamKey) trimBefore(id string) int {
@@ -295,6 +332,12 @@ func (s *streamKey) after(id string) []StreamEntry {
 	return s.entries[pos:]
 }
 
+func (s *streamKey) len() int {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return len(s.entries)
+}
+
 // get a stream entry by ID
 // Also returns the position in the entries slice, if found.
 func (s *streamKey) get(id string) (int, *StreamEntry) {
@@ -363,6 +406,8 @@ func (g *streamGroup) readGroup(
 		}
 		g.consumers[consumerID].numPendingEntries += len(msgs)
 		g.lastID = msgs[len(msgs)-1].ID
+
+		g.updateEntriesRead(msgs)
 		return msgs
 	}
 
@@ -434,6 +479,9 @@ func (s *streamKey) delete(ids []string) (int, error) {
 			continue
 		}
 
+		for _, group := range s.groups {
+			group.onDelete(entry.ID)
+		}
 		s.entries = append(s.entries[:i], s.entries[i+1:]...)
 		count++
 	}
@@ -498,3 +546,25 @@ func (g *streamGroup) setLastSuccess(c string, t time.Time) {
 	g.setLastSeen(c, t)
 	g.consumers[c].lastSuccess = t
 }
+
+func (g *streamGroup) lag() int {
+	if !g.entriesReadValid {
+		return -1
+	}
+	g.stream.mu.Lock()
+	defer g.stream.mu.Unlock()
+	return g.stream.entriesAdded - g.entriesRead
+}
+
+func (g *streamGroup) updateEntriesRead(msgs []StreamEntry) {
+	// mutex protects lastId and len(g.stream.entries) together.
+	// We should not lock the mutex  twice for each
+	g.stream.mu.Lock()
+	defer g.stream.mu.Unlock()
+	if g.entriesReadValid {
+		g.entriesRead += len(msgs)
+	} else if g.lastID == g.stream.lastIDUnlocked() {
+		// reset entries read as we catch up to the last ID
+		g.entriesRead = len(g.stream.entries)
+	}
+}