diff --git a/irc/client.go b/irc/client.go
index 8465fa6b..b5204b3d 100644
--- a/irc/client.go
+++ b/irc/client.go
@@ -146,6 +146,7 @@ type MultilineBatch struct {
 	target        string
 	responseLabel string // this is the value of the labeled-response tag sent with BATCH
 	message       utils.SplitMessage
+	lenBytes      int
 	tags          map[string]string
 }
 
@@ -168,14 +169,14 @@ func (s *Session) EndMultilineBatch(label string) (batch MultilineBatch, err err
 	s.fakelag.Unsuspend()
 
 	// heuristics to estimate how much data they used while fakelag was suspended
-	fakelagBill := (batch.message.LenBytes() / 512) + 1
+	fakelagBill := (batch.lenBytes / 512) + 1
 	fakelagBillLines := (batch.message.LenLines() * 60) / 512
 	if fakelagBill < fakelagBillLines {
 		fakelagBill = fakelagBillLines
 	}
 	s.deferredFakelagCount = fakelagBill
 
-	if batch.label == "" || batch.label != label || batch.message.LenLines() == 0 {
+	if batch.label == "" || batch.label != label || !batch.message.ValidMultiline() {
 		err = errInvalidMultilineBatch
 		return
 	}
@@ -1357,9 +1358,14 @@ func (session *Session) sendSplitMsgFromClientInternal(blocking bool, nickmask,
 				session.SendRawMessage(msg, blocking)
 			}
 		} else {
-			for i, messagePair := range message.Split {
+			msgidSent := false // send msgid on the first nonblank line
+			for _, messagePair := range message.Split {
+				if len(messagePair.Message) == 0 {
+					continue
+				}
 				var msgid string
-				if i == 0 {
+				if !msgidSent {
+					msgidSent = true
 					msgid = message.Msgid
 				}
 				session.sendFromClientInternal(blocking, message.Time, msgid, nickmask, accountName, tags, command, target, messagePair.Message)
diff --git a/irc/handlers.go b/irc/handlers.go
index 4427bdf9..467881e8 100644
--- a/irc/handlers.go
+++ b/irc/handlers.go
@@ -1793,33 +1793,39 @@ func nickHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *Resp
 
 // helper to store a batched PRIVMSG in the session object
 func absorbBatchedMessage(server *Server, client *Client, msg ircmsg.IrcMessage, batchTag string, histType history.ItemType, rb *ResponseBuffer) {
+	var errorCode, errorMessage string
+	defer func() {
+		if errorCode != "" {
+			if histType != history.Notice {
+				rb.Add(nil, server.name, "FAIL", "BATCH", errorCode, errorMessage)
+			}
+			rb.session.EndMultilineBatch("")
+		}
+	}()
+
 	if batchTag != rb.session.batch.label {
-		if histType != history.Notice {
-			rb.Add(nil, server.name, "FAIL", "BATCH", "MULTILINE_INVALID", client.t("Incorrect batch tag sent"))
-		}
-		rb.session.EndMultilineBatch("")
+		errorCode, errorMessage = "MULTILINE_INVALID", client.t("Incorrect batch tag sent")
 		return
-	} else if len(msg.Params) < 2 || msg.Params[1] == "" {
-		if histType != history.Notice {
-			rb.Add(nil, server.name, "FAIL", "BATCH", "MULTILINE_INVALID", client.t("Invalid multiline batch"))
-		}
-		rb.session.EndMultilineBatch("")
+	} else if len(msg.Params) < 2 {
+		errorCode, errorMessage = "MULTILINE_INVALID", client.t("Invalid multiline batch")
 		return
 	}
 	rb.session.batch.command = msg.Command
 	isConcat, _ := msg.GetTag(caps.MultilineConcatTag)
+	if isConcat && len(msg.Params[1]) == 0 {
+		errorCode, errorMessage = "MULTILINE_INVALID", client.t("Cannot send a blank line with the multiline concat tag")
+		return
+	}
+	if !isConcat && len(rb.session.batch.message.Split) != 0 {
+		rb.session.batch.lenBytes++ // bill for the newline
+	}
 	rb.session.batch.message.Append(msg.Params[1], isConcat)
+	rb.session.batch.lenBytes += len(msg.Params[1])
 	config := server.Config()
-	if config.Limits.Multiline.MaxBytes < rb.session.batch.message.LenBytes() {
-		if histType != history.Notice {
-			rb.Add(nil, server.name, "FAIL", "BATCH", "MULTILINE_MAX_BYTES", strconv.Itoa(config.Limits.Multiline.MaxBytes))
-		}
-		rb.session.EndMultilineBatch("")
+	if config.Limits.Multiline.MaxBytes < rb.session.batch.lenBytes {
+		errorCode, errorMessage = "MULTILINE_MAX_BYTES", strconv.Itoa(config.Limits.Multiline.MaxBytes)
 	} else if config.Limits.Multiline.MaxLines != 0 && config.Limits.Multiline.MaxLines < rb.session.batch.message.LenLines() {
-		if histType != history.Notice {
-			rb.Add(nil, server.name, "FAIL", "BATCH", "MULTILINE_MAX_LINES", strconv.Itoa(config.Limits.Multiline.MaxLines))
-		}
-		rb.session.EndMultilineBatch("")
+		errorCode, errorMessage = "MULTILINE_MAX_LINES", strconv.Itoa(config.Limits.Multiline.MaxLines)
 	}
 }
 
diff --git a/irc/utils/text.go b/irc/utils/text.go
index 5d46b140..62c49eb5 100644
--- a/irc/utils/text.go
+++ b/irc/utils/text.go
@@ -67,14 +67,14 @@ func (sm *SplitMessage) LenLines() int {
 	return len(sm.Split)
 }
 
-func (sm *SplitMessage) LenBytes() (result int) {
-	if sm.Split == nil {
-		return len(sm.Message)
-	}
+func (sm *SplitMessage) ValidMultiline() bool {
+	// must contain at least one nonblank line
 	for i := 0; i < len(sm.Split); i++ {
-		result += len(sm.Split[i].Message)
+		if len(sm.Split[i].Message) != 0 {
+			return true
+		}
 	}
-	return
+	return false
 }
 
 func (sm *SplitMessage) IsRestrictedCTCPMessage() bool {