1 files changed, 6 insertions, 3 deletions
diff --git a/lib/Spreadsheet/ParseXLSX.pm b/lib/Spreadsheet/ParseXLSX.pm
index 8159fa8..209ae6f 100644
--- a/lib/Spreadsheet/ParseXLSX.pm
+++ b/lib/Spreadsheet/ParseXLSX.pm
@@ -575,9 +575,12 @@ sub _cell_to_row_col {
 
     my ($col, $row) = $cell =~ /([A-Z]+)([0-9]+)/;
 
-    (my $ncol = $col) =~ tr/A-Z/1-9A-Q/;
-    $ncol = POSIX::strtol($ncol, 27);
-    $ncol -= 1;
+    my $ncol = 0;
+    for my $char (split //, $col) {
+        $ncol *= 26;
+        $ncol += ord($char) - ord('A') + 1;
+    }
+    $ncol = $ncol - 1;
 
     my $nrow = $row - 1;