About the document
- Who files:
- Married couple with section 40(1)–(8) income
- 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/2568/241268Mix90.pdf
What this document is
If spouses have income beyond employment (rent, profession, business, interest and more), they may file one ภ.ง.ด.90 together — “รวมคำนวณภาษี”. Instead of the regular allowance attachment they enclose “รายละเอียดแนบ ภ.ง.ด.90 กรณีรวมคำนวณภาษี” with “taxpayer”, “spouse” and “total” columns.
The form has ten pages: four pages of the return and six of the attachment. The return lines show both spouses’ totals.
Who files and where
- married couples with section 40(1)–(8) income; if both have only salary, ภ.ง.ด.91 fits;
- joint computation is optional: with the progressive scale it is often more expensive than two separate returns — compare;
- the option “spouse’s salary separately, other income jointly” (แยกยื่นเฉพาะมาตรา 40 (1)) is not covered by this document;
- 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;
- each spouse’s income by type (items 1–7): salary, copyright, interest and dividends, rent, professions, contracting, business; expenses by each spouse’s own rules;
- property sales taxed separately (item 8) and gifts taxed at 5% (item 9) — for each spouse;
- each spouse’s allowances with their own limits: personal 60,000, children, own parents, insurance, funds, mortgage, social security and more.
What to bring
- both spouses’ 50 ทวิ certificates, rental contracts and income records;
- expense records if you deduct actual expenses;
- insurer, fund and bank certificates; ล.ย.03 and ล.ย.04 for the related allowances.
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 expenses and the 190,000 exemption for each spouse, allowances, the tax scale and the “0.5% of income” on the total.
- 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.