diff --git a/app/Models/Invoice.php b/app/Models/Invoice.php
index 4f2100e23d2e..6103eb86e67b 100644
--- a/app/Models/Invoice.php
+++ b/app/Models/Invoice.php
@@ -60,6 +60,7 @@ class Invoice extends EntityModel implements BalanceAffecting
         'counter',
         'custom1',
         'custom2',
+        'idNumber',
         'userId',
         'year',
         'date:',
diff --git a/app/Models/Traits/GeneratesNumbers.php b/app/Models/Traits/GeneratesNumbers.php
index 0353c80f4be6..8cda08d0af60 100644
--- a/app/Models/Traits/GeneratesNumbers.php
+++ b/app/Models/Traits/GeneratesNumbers.php
@@ -115,7 +115,7 @@ trait GeneratesNumbers
     {
         $pattern = $invoice->invoice_type_id == INVOICE_TYPE_QUOTE ? $this->quote_number_pattern : $this->invoice_number_pattern;
 
-        return strstr($pattern, '$custom');
+        return strstr($pattern, '$custom') || strstr($pattern, '$idNumber');
     }
 
     /**
@@ -176,11 +176,13 @@ trait GeneratesNumbers
         $search = [
             '{$custom1}',
             '{$custom2}',
+            '{$idNumber}',
         ];
 
         $replace = [
             $invoice->client->custom_value1,
             $invoice->client->custom_value2,
+            $invoice->client->id_number,
         ];
 
         return str_replace($search, $replace, $pattern);
diff --git a/resources/views/invoices/edit.blade.php b/resources/views/invoices/edit.blade.php
index 755dcad0229b..6958eff5a240 100644
--- a/resources/views/invoices/edit.blade.php
+++ b/resources/views/invoices/edit.blade.php
@@ -1596,6 +1596,7 @@
         var number = '{{ $account->applyNumberPattern($invoice) }}';
         number = number.replace('{$custom1}', client.custom_value1 ? client.custom_value1 : '');
         number = number.replace('{$custom2}', client.custom_value2 ? client.custom_value1 : '');
+        number = number.replace('{$idNumber}', client.id_number ? client.id_number : '');
         model.invoice().invoice_number(number);
     }