diff --git a/internal/export/idna/idna10.0.0.go b/internal/export/idna/idna10.0.0.go
index 0e7571d1..01bdbb16 100644
--- a/internal/export/idna/idna10.0.0.go
+++ b/internal/export/idna/idna10.0.0.go
@@ -348,7 +348,7 @@ func (p *Profile) process(s string, toASCII bool) (string, error) {
 	// TODO: allow for a quick check of the tables data.
 	// It seems like we should only create this error on ToASCII, but the
 	// UTS 46 conformance tests suggests we should always check this.
-	if err == nil && p.verifyDNSLength && s == "" {
+	if err == nil && p.verifyDNSLength && (s == "" || s[len(s)-1] == '.') {
 		err = &labelError{s, "A4"}
 	}
 	labels := labelIter{orig: s}
@@ -413,12 +413,9 @@ func (p *Profile) process(s string, toASCII bool) (string, error) {
 	}
 	s = labels.result()
 	if toASCII && p.verifyDNSLength && err == nil {
-		// Compute the length of the domain name minus the root label and its dot.
+		// Compute the length of the domain name.
 		n := len(s)
-		if n > 0 && s[n-1] == '.' {
-			n--
-		}
-		if len(s) < 1 || n > 253 {
+		if n < 1 || n > 253 {
 			err = &labelError{s, "A4"}
 		}
 	}
diff --git a/internal/export/idna/idna10.0.0_test.go b/internal/export/idna/idna10.0.0_test.go
index c3365bc6..ff9218dd 100644
--- a/internal/export/idna/idna10.0.0_test.go
+++ b/internal/export/idna/idna10.0.0_test.go
@@ -67,7 +67,12 @@ func TestLabelErrors(t *testing.T) {
 		{lengthA, ".b", ".b", "A4"},
 		{lengthA, "\u3002b", ".b", "A4"},
 		{lengthA, "..b", "..b", "A4"},
-		{lengthA, "b..", "b..", ""},
+		{lengthA, "b.", "b.", "A4"},
+		{lengthA, "ƀ.", "xn--lha.", "A4"},
+		{lengthA, "b..", "b..", "A4"},
+		{lengthA, "ƀ..", "xn--lha..", "A4"},
+		{lengthA, "b...", "b...", "A4"},
+		{lengthA, "ƀ...", "xn--lha...", "A4"},
 
 		// Sharpened Bidi rules for Unicode 10.0.0. Apply for ALL labels in ANY
 		// of the labels is RTL.
@@ -80,7 +85,12 @@ func TestLabelErrors(t *testing.T) {
 		{resolve, ".b", ".b", ""},
 		{resolve, "\u3002b", ".b", ""},
 		{resolve, "..b", "..b", ""},
+		{resolve, "b.", "b.", ""},
+		{resolve, "ƀ.", "xn--lha.", ""},
 		{resolve, "b..", "b..", ""},
+		{resolve, "ƀ..", "xn--lha..", ""},
+		{resolve, "b...", "b...", ""},
+		{resolve, "ƀ...", "xn--lha...", ""},
 		{resolve, "\xed", "", "P1"},
 
 		// Raw punycode
diff --git a/internal/export/idna/idna9.0.0.go b/internal/export/idna/idna9.0.0.go
index f217b1a4..017335c9 100644
--- a/internal/export/idna/idna9.0.0.go
+++ b/internal/export/idna/idna9.0.0.go
@@ -348,7 +348,7 @@ func (p *Profile) process(s string, toASCII bool) (string, error) {
 	}
 	// It seems like we should only create this error on ToASCII, but the
 	// UTS 46 conformance tests suggests we should always check this.
-	if err == nil && p.verifyDNSLength && s == "" {
+	if err == nil && p.verifyDNSLength && (s == "" || s[len(s)-1] == '.') {
 		err = &labelError{s, "A4"}
 	}
 	labels := labelIter{orig: s}
@@ -404,12 +404,9 @@ func (p *Profile) process(s string, toASCII bool) (string, error) {
 	}
 	s = labels.result()
 	if toASCII && p.verifyDNSLength && err == nil {
-		// Compute the length of the domain name minus the root label and its dot.
+		// Compute the length of the domain name.
 		n := len(s)
-		if n > 0 && s[n-1] == '.' {
-			n--
-		}
-		if len(s) < 1 || n > 253 {
+		if n < 1 || n > 253 {
 			err = &labelError{s, "A4"}
 		}
 	}
diff --git a/internal/export/idna/idna9.0.0_test.go b/internal/export/idna/idna9.0.0_test.go
index 91a1e90d..393e7074 100644
--- a/internal/export/idna/idna9.0.0_test.go
+++ b/internal/export/idna/idna9.0.0_test.go
@@ -71,13 +71,23 @@ func TestLabelErrors(t *testing.T) {
 		{lengthA, ".b", "b", ""},
 		{lengthA, "\u3002b", "b", ""},
 		{lengthA, "..b", "b", ""},
-		{lengthA, "b..", "b..", ""},
+		{lengthA, "b.", "b.", "A4"},
+		{lengthA, "ƀ.", "xn--lha.", "A4"},
+		{lengthA, "b..", "b..", "A4"},
+		{lengthA, "ƀ..", "xn--lha..", "A4"},
+		{lengthA, "b...", "b...", "A4"},
+		{lengthA, "ƀ...", "xn--lha...", "A4"},
 
 		{resolve, "a..b", "a..b", ""},
 		{resolve, ".b", "b", ""},
 		{resolve, "\u3002b", "b", ""},
 		{resolve, "..b", "b", ""},
+		{resolve, "b.", "b.", ""},
+		{resolve, "ƀ.", "xn--lha.", ""},
 		{resolve, "b..", "b..", ""},
+		{resolve, "ƀ..", "xn--lha..", ""},
+		{resolve, "b...", "b...", ""},
+		{resolve, "ƀ...", "xn--lha...", ""},
 		{resolve, "\xed", "", "P1"},
 
 		// Raw punycode