diff --git a/spec/unit/room-state.spec.js b/spec/unit/room-state.spec.js
index 3c1b0e97d..1608fd4aa 100644
--- a/spec/unit/room-state.spec.js
+++ b/spec/unit/room-state.spec.js
@@ -529,13 +529,53 @@ describe("RoomState", function() {
         });
     });
 
+    describe("getJoinedMemberCount", function() {
+        beforeEach(() => {
+            state = new RoomState(roomId);
+        });
+        
+        it("should update after adding joined member", function() {
+            state.setStateEvents([
+                utils.mkMembership({event: true, mship: "join",
+                    user: userA, room: roomId}),
+            ]);
+            expect(state.getJoinedMemberCount()).toEqual(1);
+            state.setStateEvents([
+                utils.mkMembership({event: true, mship: "join",
+                    user: userC, room: roomId}),
+            ]);
+            expect(state.getJoinedMemberCount()).toEqual(2);
+        });
+    });
+
+    describe("getInvitedMemberCount", function() {
+        beforeEach(() => {
+            state = new RoomState(roomId);
+        });
+        
+        it("should update after adding invited member", function() {
+            state.setStateEvents([
+                utils.mkMembership({event: true, mship: "invite",
+                    user: userA, room: roomId}),
+            ]);
+            expect(state.getInvitedMemberCount()).toEqual(1);
+            state.setStateEvents([
+                utils.mkMembership({event: true, mship: "invite",
+                    user: userC, room: roomId}),
+            ]);
+            expect(state.getInvitedMemberCount()).toEqual(2);
+        });
+    });
+
     describe("setJoinedMemberCount", function() {
+        beforeEach(() => {
+            state = new RoomState(roomId);
+        });
+        
         it("should, once used, override counting members from state", function() {
             state.setStateEvents([
                 utils.mkMembership({event: true, mship: "join",
                     user: userA, room: roomId}),
-                utils.mkMembership({event: true, mship: "invite",
-                    user: userB, room: roomId}),
             ]);
             expect(state.getJoinedMemberCount()).toEqual(1);
             state.setJoinedMemberCount(100);
@@ -552,8 +592,6 @@ describe("RoomState", function() {
             state.setStateEvents([
                 utils.mkMembership({event: true, mship: "join",
                     user: userA, room: roomId}),
-                utils.mkMembership({event: true, mship: "invite",
-                    user: userB, room: roomId}),
             ]);
             state.setJoinedMemberCount(100);
             const copy = state.clone();
@@ -565,6 +603,42 @@ describe("RoomState", function() {
         });
     });
 
+    describe("setInvitedMemberCount", function() {
+        beforeEach(() => {
+            state = new RoomState(roomId);
+        });
+
+        it("should, once used, override counting members from state", function() {
+            state.setStateEvents([
+                utils.mkMembership({event: true, mship: "invite",
+                    user: userB, room: roomId}),
+            ]);
+            expect(state.getInvitedMemberCount()).toEqual(1);
+            state.setInvitedMemberCount(100);
+            expect(state.getInvitedMemberCount()).toEqual(100);
+            state.setStateEvents([
+                utils.mkMembership({event: true, mship: "invite",
+                    user: userC, room: roomId}),
+            ]);
+            expect(state.getInvitedMemberCount()).toEqual(100);
+        });
+
+        it("should, once used, override counting members from state, " +
+        "also after clone", function() {
+            state.setStateEvents([
+                utils.mkMembership({event: true, mship: "invite",
+                    user: userB, room: roomId}),
+            ]);
+            state.setInvitedMemberCount(100);
+            const copy = state.clone();
+            copy.setStateEvents([
+                utils.mkMembership({event: true, mship: "invite",
+                    user: userC, room: roomId}),
+            ]);
+            expect(state.getInvitedMemberCount()).toEqual(100);
+        });
+    });
+
     describe("maySendEvent", function() {
         it("should say non-joined members may not send events",
         function() {
diff --git a/src/models/room-state.js b/src/models/room-state.js
index 65a6784c8..1cbf93a5d 100644
--- a/src/models/room-state.js
+++ b/src/models/room-state.js
@@ -376,6 +376,7 @@ RoomState.prototype._updateMember = function(member) {
 
     this.members[member.userId] = member;
     this._joinedMemberCount = null;
+    this._invitedMemberCount = null;
 };
 
 /**