Articles | Updated 22 October 2026
Can you issue tax invoices in Excel, and what to watch for
Yes. The Revenue Department has ruled that a full tax invoice produced entirely by computer is allowed without prior approval. But it must carry every required item, have a running number, must not be edited after issue, and copies must be kept at least 5 years. These are exactly where Excel slips most easily
5 risks of tax invoices made in Excel
Tax invoice no.
What the law says: A running number is required. Without one the buyer cannot use it as input tax
Why Excel slips: Copying an old file and forgetting to change the number, so numbers repeat or skip
Editing after issue
What the law says: A full tax invoice must not be struck out, erased or added to. If altered, the buyer cannot claim the input tax
Why Excel slips: Reopening the file, changing figures and reprinting under the same number
Invoice copies
What the law says: Copies must be made and kept at least 5 years from issue
Why Excel slips: Files get overwritten or live on one computer that can fail
Missing items
What the law says: Every item is required, such as the words tax invoice, tax ID, head office or branch and VAT shown apart from price
Why Excel slips: Old templates lack a branch field, or the VAT formula is dragged into the wrong row
Invoices issued as a set
What the law says: Issued as a set with other documents, it must say issued as a set and the copy must say tax invoice copy. If the invoice is fully computer-made, these words must come from the computer, not a rubber stamp
Why Excel slips: Printing once and photocopying, or stamping the word copy by hand
| Risk | What the law says | Why Excel slips |
|---|---|---|
| Tax invoice no. | A running number is required. Without one the buyer cannot use it as input tax | Copying an old file and forgetting to change the number, so numbers repeat or skip |
| Editing after issue | A full tax invoice must not be struck out, erased or added to. If altered, the buyer cannot claim the input tax | Reopening the file, changing figures and reprinting under the same number |
| Invoice copies | Copies must be made and kept at least 5 years from issue | Files get overwritten or live on one computer that can fail |
| Missing items | Every item is required, such as the words tax invoice, tax ID, head office or branch and VAT shown apart from price | Old templates lack a branch field, or the VAT formula is dragged into the wrong row |
| Invoices issued as a set | Issued as a set with other documents, it must say issued as a set and the copy must say tax invoice copy. If the invoice is fully computer-made, these words must come from the computer, not a rubber stamp | Printing once and photocopying, or stamping the word copy by hand |
If you still use Excel, do this
For the full list of required items, see the article on what a correct tax invoice must contain
- Keep a separate number register and record each new number before issuing
- Save each issued invoice as a locked PDF and never edit the original file
- If an invoice already sent is wrong, issue a credit or debit note referring to it instead of changing it
- Back up the copies folder elsewhere, such as online storage, and keep it at least 5 years
- Check your template against the required items once a year
How to do it in the app
In GORINY, full tax invoices are issued from the sales page with document numbers that run on automatically. Issued documents cannot be edited; a wrong bill gets a credit or debit note referring to it. Totals reach the output tax report matching what the customer holds, and documents stay in a system backed up every night
Frequently asked questions
- Do I need permission to issue tax invoices from Excel?
- A full tax invoice made entirely by computer needs no prior approval, per the Revenue Department ruling, but every required item must be there
- I sent a tax invoice and found a mistake. Can I fix the original?
- No. A full tax invoice must not be altered. Issue a credit or debit note referring to it
- What if a tax invoice has no number?
- The buyer cannot use it as input tax, and the issuer commits the offence of incomplete items, with a fine of up to 2,000 baht
Sources
Checked against official announcements on 22 October 2026
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