diff --git a/modules/rtp_rtcp/source/rtp_sender.cc b/modules/rtp_rtcp/source/rtp_sender.cc
index f1f7544b92..b057d6db0b 100644
--- a/modules/rtp_rtcp/source/rtp_sender.cc
+++ b/modules/rtp_rtcp/source/rtp_sender.cc
@@ -113,6 +113,7 @@ bool IsNonVolatile(RTPExtensionType type) {
     case kRtpExtensionTransportSequenceNumber:
     case kRtpExtensionTransportSequenceNumber02:
     case kRtpExtensionRtpStreamId:
+    case kRtpExtensionRepairedRtpStreamId:
     case kRtpExtensionMid:
     case kRtpExtensionGenericFrameDescriptor00:
     case kRtpExtensionGenericFrameDescriptor02:
@@ -124,7 +125,6 @@ bool IsNonVolatile(RTPExtensionType type) {
     case kRtpExtensionVideoContentType:
     case kRtpExtensionVideoLayersAllocation:
     case kRtpExtensionVideoTiming:
-    case kRtpExtensionRepairedRtpStreamId:
     case kRtpExtensionColorSpace:
     case kRtpExtensionVideoFrameTrackingId:
       return false;
@@ -747,20 +747,23 @@ void RTPSender::UpdateHeaderSizes() {
       rtp_header_length + RtpHeaderExtensionSize(kFecOrPaddingExtensionSizes,
                                                  rtp_header_extension_map_);
 
-  // RtpStreamId and Mid are treated specially in that we check if they
-  // currently are being sent. RepairedRtpStreamId is ignored because it is sent
-  // instead of RtpStreamId on rtx packets and require the same size.
+  // RtpStreamId, Mid and RepairedRtpStreamId are treated specially in that
+  // we check if they currently are being sent. RepairedRtpStreamId can be
+  // sent instead of RtpStreamID on RTX packets and may share the same space.
+  // When the primary SSRC has already been acked but the RTX SSRC has not
+  // yet been acked, RepairedRtpStreamId needs to be taken into account
+  // separately.
   const bool send_mid_rid_on_rtx =
-      rtx_ssrc_.has_value() && !rtx_ssrc_has_acked_;
-  const bool send_mid_rid =
-      always_send_mid_and_rid_ || !ssrc_has_acked_ || send_mid_rid_on_rtx;
+      rtx_ssrc_.has_value() &&
+      (always_send_mid_and_rid_ || !rtx_ssrc_has_acked_);
+  const bool send_mid_rid = always_send_mid_and_rid_ || !ssrc_has_acked_;
   std::vector<RtpExtensionSize> non_volatile_extensions;
   for (auto& extension :
        audio_configured_ ? AudioExtensionSizes() : VideoExtensionSizes()) {
     if (IsNonVolatile(extension.type)) {
       switch (extension.type) {
         case RTPExtensionType::kRtpExtensionMid:
-          if (send_mid_rid && !mid_.empty()) {
+          if ((send_mid_rid || send_mid_rid_on_rtx) && !mid_.empty()) {
             non_volatile_extensions.push_back(extension);
           }
           break;
@@ -769,6 +772,11 @@ void RTPSender::UpdateHeaderSizes() {
             non_volatile_extensions.push_back(extension);
           }
           break;
+        case RTPExtensionType::kRtpExtensionRepairedRtpStreamId:
+          if (send_mid_rid_on_rtx && !send_mid_rid && !rid_.empty()) {
+            non_volatile_extensions.push_back(extension);
+          }
+          break;
         default:
           non_volatile_extensions.push_back(extension);
       }
diff --git a/modules/rtp_rtcp/source/rtp_sender_unittest.cc b/modules/rtp_rtcp/source/rtp_sender_unittest.cc
index c9e98ff3c3..432c5e72d3 100644
--- a/modules/rtp_rtcp/source/rtp_sender_unittest.cc
+++ b/modules/rtp_rtcp/source/rtp_sender_unittest.cc
@@ -921,6 +921,39 @@ TEST_F(RtpSenderTest, CountMidOnlyUntilAcked) {
   EXPECT_EQ(rtp_sender_->ExpectedPerPacketOverhead(), 12u);
 }
 
+TEST_F(RtpSenderTest, CountMidRidRridUntilAcked) {
+  RtpRtcpInterface::Configuration config = GetDefaultConfig();
+  CreateSender(config);
+
+  // Base RTP overhead is 12B and we use RTX which has an additional 2 bytes
+  // overhead.
+  EXPECT_EQ(rtp_sender_->ExpectedPerPacketOverhead(), 14u);
+
+  rtp_sender_->RegisterRtpHeaderExtension(RtpMid::Uri(), kMidExtensionId);
+
+  // Counted only if set.
+  EXPECT_EQ(rtp_sender_->ExpectedPerPacketOverhead(), 14u);
+  rtp_sender_->SetMid("foo");
+  EXPECT_EQ(rtp_sender_->ExpectedPerPacketOverhead(), 38u);
+
+  rtp_sender_->RegisterRtpHeaderExtension(RtpStreamId::Uri(), kRidExtensionId);
+  EXPECT_EQ(rtp_sender_->ExpectedPerPacketOverhead(), 54u);
+
+  // mid/rrid may be shared with mid/rid when both are active.
+  rtp_sender_->RegisterRtpHeaderExtension(RepairedRtpStreamId::Uri(),
+                                          kRepairedRidExtensionId);
+  EXPECT_EQ(rtp_sender_->ExpectedPerPacketOverhead(), 54u);
+
+  // Ack received, mid/rid no longer sent but we still need space for
+  // mid/rrid which can no longer be shared with mid/rid.
+  rtp_sender_->OnReceivedAckOnSsrc(0);
+  EXPECT_EQ(rtp_sender_->ExpectedPerPacketOverhead(), 54u);
+
+  // Ack received for RTX, no need to send RRID anymore.
+  rtp_sender_->OnReceivedAckOnRtxSsrc(0);
+  EXPECT_EQ(rtp_sender_->ExpectedPerPacketOverhead(), 14u);
+}
+
 TEST_F(RtpSenderTest, DontCountVolatileExtensionsIntoOverhead) {
   RtpRtcpInterface::Configuration config = GetDefaultConfig();
   config.rtx_send_ssrc = {};