diff --git a/bin/pt-online-schema-change b/bin/pt-online-schema-change
index 00b8deab..f057bedc 100755
--- a/bin/pt-online-schema-change
+++ b/bin/pt-online-schema-change
@@ -5279,9 +5279,9 @@ sub one_nibble {
    return $self->{one_nibble};
 }
 
-sub chunk_size {
+sub limit {
    my ($self) = @_;
-   return $self->{limit} + 1;
+   return $self->{limit};
 }
 
 sub set_chunk_size {
@@ -8594,7 +8594,7 @@ sub main {
          my $expl = explain_statement(
             tbl  => $tbl,
             sth  => $sth->{explain_upper_boundary},
-            vals => [ @{$boundary->{lower}}, $nibble_iter->chunk_size() ],
+            vals => [ @{$boundary->{lower}}, $nibble_iter->limit() ],
          );
          if (lc($expl->{key} || '') ne lc($nibble_iter->nibble_index() || '')) {
             my $msg
@@ -8609,7 +8609,7 @@ sub main {
                . $sth->{upper_boundary}->{Statement}
                . " with values "
                . join(", ", map { defined $_ ? $_ : "NULL" }
-                      (@{$boundary->{lower}}, $nibble_iter->chunk_size()))
+                      (@{$boundary->{lower}}, $nibble_iter->limit()))
                . "\n";
             die $msg;
          } 
diff --git a/bin/pt-table-checksum b/bin/pt-table-checksum
index f6741552..9982e731 100755
--- a/bin/pt-table-checksum
+++ b/bin/pt-table-checksum
@@ -6055,9 +6055,9 @@ sub one_nibble {
    return $self->{one_nibble};
 }
 
-sub chunk_size {
+sub limit {
    my ($self) = @_;
-   return $self->{limit} + 1;
+   return $self->{limit};
 }
 
 sub set_chunk_size {
@@ -9533,7 +9533,7 @@ sub main {
          my $expl = explain_statement(
             tbl  => $tbl,
             sth  => $sth->{explain_upper_boundary},
-            vals => [ @{$boundary->{lower}}, $nibble_iter->chunk_size() ],
+            vals => [ @{$boundary->{lower}}, $nibble_iter->limit() ],
          );
          if (   lc($expl->{key} || '')
              ne lc($nibble_iter->nibble_index() || '') ) {
diff --git a/lib/NibbleIterator.pm b/lib/NibbleIterator.pm
index 7edabdc3..0d2c0898 100644
--- a/lib/NibbleIterator.pm
+++ b/lib/NibbleIterator.pm
@@ -405,9 +405,9 @@ sub one_nibble {
    return $self->{one_nibble};
 }
 
-sub chunk_size {
+sub limit {
    my ($self) = @_;
-   return $self->{limit} + 1;
+   return $self->{limit};
 }
 
 sub set_chunk_size {
diff --git a/t/lib/NibbleIterator.t b/t/lib/NibbleIterator.t
index 76075167..eef3c7d0 100644
--- a/t/lib/NibbleIterator.t
+++ b/t/lib/NibbleIterator.t
@@ -206,9 +206,9 @@ ok(
 );
 
 is(
-   $ni->chunk_size(),
-   5,
-   "chunk_size()"
+   $ni->limit(),
+   4,
+   "limit()"
 );
 
 # ############################################################################