What documents does my accountant need from me each month?
Every sales and purchase tax invoice, every receipt, the bank statements for every account, payroll for the month, and every withholding tax certificate you issued or received. Your accountant needs them early in the following month, because the withholding returns are due on the 7th (15th online) and the VAT return on the 15th (23rd online), and a document that arrives after the filing is a correction, not an entry.
Last reviewed 2 November 2026
The list
| Document | Why the accountant needs it |
|---|---|
| Sales tax invoices and receipts you issued | They are your output VAT and your revenue. A VAT registrant must issue a tax invoice for every sale, immediately (Revenue Code section 86). |
| Purchase tax invoices from suppliers | They are your input VAT. Without the supplier’s tax invoice there is nothing to claim. |
| Receipts and bills for other expenses | Supporting documents for every entry. No document, no deductible expense. |
| Bank statements, every account, full month | The reconciliation that catches what was never invoiced. |
| Withholding certificates you issued (50 Tawi) | The basis for PND 3 and PND 53. |
| Withholding certificates you received from customers | Tax already paid on your behalf, credited against your corporate tax at year end. They are easy to lose and they are money. |
| Payroll: salaries, joiners, leavers | For PND 1 and the monthly social security return. |
| Import paperwork if you import | Customs declarations and receipts support the VAT paid at the border. |
| Contracts for anything new: leases, loans, assets bought | They decide how an item is booked, and some create withholding or stamp duty of their own. |
The dates that set the deadline for you
The accountant’s deadline is the filing calendar, so yours is a few days before it. The withholding returns (PND 1, 3 and 53) are due within 7 days of the month end, 15 if filed online; the VAT return (PP 30) by the 15th, or the 23rd online. Every date is on the compliance calendar.
- Withholding certificates are issued at the moment you withhold. For payments other than salary, the payer must issue the certificate immediately each time tax is withheld (Revenue Code section 50 bis). For salaries, by 15 February of the following year, or within a month of the employee leaving.
- VAT reports run on a 3 working day clock. A VAT registrant must enter each purchase and sale in its VAT reports within 3 working days (section 87). That is why a firm asks for documents weekly rather than once a month.
- The books themselves have a 15 day clock. The DBD’s 2001 notification on mandatory accounts requires daily accounts to be written up within 15 days of the transaction and the ledger within 15 days of the month end.
The late purchase invoice
Input VAT is normally claimed in the month shown on the supplier’s tax invoice. Where there is a necessary cause for missing that month, it may be claimed later, but not more than six months from the month after the invoice was issued (Director-General VAT Notification No. 4, as amended by No. 76). After that the route narrows to amending the return for the original month. A purchase invoice found in a drawer in December is often VAT you have already lost.
What a monthly fee covers is on what is actually included in a bookkeeping fee. If your current firm never asks for half of this list, it may be worth three quotes from firms that do.
Related questions
- What is actually included in a Thai bookkeeping fee, and what almost never is?
- What happens if you file PP 30 late?
- PND 1 or PND 1 Kor: which one, and when?
Sources
- Revenue Code sections 86 and 86/4, tax invoices (Revenue Department, English)
- Revenue Code section 87, VAT reports (Revenue Department, English)
- Revenue Code section 50 bis, withholding tax certificates (Revenue Department, English)
- Director-General VAT Notification No. 4, input tax claimed in a later month (Thai)
- Director-General VAT Notification No. 76, amending No. 4: the six month limit (Thai)
- DBD Notification B.E. 2544 on mandatory accounts and periods for recording entries, English translation (PDF)
- Revenue Department: baseline filing deadlines for PND 1, 3, 53, PP 30 and PND 50
This is general information about how a filing works, not accounting or tax advice for your company. Confirm anything that matters against the official notice or with your accountant. Spotted something out of date? Tell us and we will fix it.