About the document
- Who files:
- Married couple, both with employment income only
- Where to submit:
- สำนักงานสรรพากรพื้นที่สาขา or by post (Bangkok)
- Authority:
- กรมสรรพากร (Revenue Department)
- Country:
- Thailand
- Category:
- Personal income tax
- How to fill:
- Cards with hints → original form → PDF
- Price:
- Free
- Last updated:
- Official source:
- https://www.rd.go.th/fileadmin/tax_pdf/pit/2568/241268Mix91.pdf
What this document is
Spouses who both have employment income only (section 40(1)) may file one ภ.ง.ด.91 together — “รวมคำนวณภาษี”. Instead of the regular allowance attachment they enclose “รายละเอียดแนบ ภ.ง.ด.91 กรณีรวมคำนวณภาษี” with “taxpayer”, “spouse” and “total” columns.
The form has four pages: two pages of the return and two of this attachment. The regular attachment is not completed in joint filing (Ins91 instructions).
Who files and where
- legally married spouses who both have employment income only; any other income requires ภ.ง.ด.90;
- joint computation is optional: because of the progressive scale it is often more expensive than two separate returns — compare both;
- paper filing from 1 January to 31 March 2569 at a สำนักงานสรรพากรพื้นที่สาขา; Bangkok residents may send it by registered mail;
- tax of 3,000 baht or more can be paid in three instalments: by 31 March, 30 April and 31 May 2569.
What the form asks
- both spouses’ taxpayer IDs, names, dates of birth and the address;
- income and withheld tax from each spouse’s 50 ทวิ, the employers’ taxpayer IDs;
- each spouse’s allowances with their own limits: personal 60,000, children, own parents, insurance, funds, mortgage, social security, Thai ESG and more;
- optionally, part of the tax to a political party — separately for each spouse.
What to bring
- both spouses’ 50 ทวิ certificates;
- insurer, fund and bank (mortgage interest) certificates, donation receipts;
- ล.ย.03 for parent support; ล.ย.04 for disabled-person care.
Check the exact list with the Revenue Department office or call 1161.
How to fill it in with FoxDocs
- Tell the chat about both spouses’ income, children, parents and expenses.
- The code fills the attachment columns, applies 50% expenses (up to 100,000 each), allowances, the tax scale on the combined total and the result.
- Check the form, download the PDF, sign it and file it.
Source
Revenue Department forms and instructions: rd.go.th — แบบแสดงรายการภาษีเงินได้บุคคลธรรมดา ปีภาษี 2568; rules for spouses — คำชี้แจงกรมสรรพากร: สามีและภริยา (ฉบับที่ 2). Checked 2026-10-15. This is not legal advice.