13th Month Bonus Tax Calculator
How a 13th-Month Salary or Tet Bonus Is Taxed in Vietnam (2026)
One-line answer: A 13th-month salary or Tet bonus is taxed as ordinary employment income, added to the salary of the single month it is paid, so the lump-sum bonus often jumps that month into a higher personal income tax band. It is not subject to social, health, or unemployment insurance. Spreading the same bonus across all 12 months would be taxed more lightly, and the calculator above shows exactly how much that bracket jump costs.
Built by HAPRI, the Health and Agricultural Policy Research Institute, an independent public-policy research institute in Vietnam. Legal basis: Personal Income Tax Law 109/2025/QH15 (Article 9 progressive schedule; bonus taxed as salary in the month received), Circular 111/2013/TT-BTC (Article 9 deductions), and the Labour Code 45/2019/QH14 (Article 104 bonus definition), with the bonus excluded from the social-insurance base per Social Insurance Law 41/2024/QH15 (Article 31.1.d). Published: 3 June 2026 · Last updated: 3 June 2026 · Law last verified: 3 June 2026 against the Ministry of Justice National Legal Portal (phapluat.gov.vn).
1. Quick answer
In Vietnam, a 13th-month salary (lương tháng 13) and a Tet bonus (thưởng Tết) are both taxable employment income, exactly like your monthly wage. Under the standard lump-sum method that Vietnamese payroll uses, the whole bonus is added to your salary in the month it is paid, and personal income tax (PIT) is worked out on the combined amount. Because the tax bands are progressive (5%, 10%, 20%, 30%, 35%), a big one-off bonus can push that month into a higher band, so the bonus is taxed at a higher marginal rate than your salary normally faces.
The bonus is not charged social, health, or unemployment insurance, so insurance does not change in the bonus month. A worker earning 25 million a month with one dependant who receives a 25 million bonus pays about 2,033,750 VND of PIT on that bonus and keeps 22,966,250 VND of it. Had the same 25 million been spread evenly across 12 months, the tax would have been about 783,750 VND lower. That gap is the "bracket-jump penalty" the calculator measures.
2. How the bonus tax is calculated, step by step
Vietnam has no separate "bonus tax". A 13th-month salary or Tet bonus is treated as ordinary salary income and runs through the same monthly PIT machinery, with one important quirk: the whole bonus lands in one month. The calculator above models exactly the steps below.
The key rule, insurance ignores the bonus. Compulsory social insurance (BHXH 8%), health insurance (BHYT 1.5%), and unemployment insurance (BHTN 1%) are charged on your labour-contract salary only. A 13th-month payment and Tet/KPI bonuses are excluded from that contribution base (Social Insurance Law 41/2024/QH15 Article 31.1.d, with the exclusion of bonuses confirmed by Circular 06/2021/TT-BLDTBXH Article 3 and Official Letters 560/LDTBXH-BHXH and 1198/CTL&BHXH-BHXH). So your insurance figure is the same in the bonus month as in every other month, and only the PIT changes.
The lump-sum method (standard Vietnamese practice)
- Work out insurance on your salary only (not salary plus bonus). For a salary up to 50,600,000 VND a month this is simply 10.5% of salary; above that, two caps split the calculation (see the parameters table below).
- Work out your family deductions: 15,500,000 VND for yourself plus 6,200,000 VND for each registered dependant.
- Normal month PIT: apply the progressive bands to
salary − insurance − deductions. This is what you pay in each of the 11 months without a bonus. - Bonus month PIT: apply the same bands to
(salary + bonus) − insurance − deductions. Because the bonus is added on top, this month's taxable income is much larger and may reach into higher bands. - The tax on the bonus is the difference:
bonus-month PIT − normal-month PIT. What you keep of the bonus isbonus − tax on the bonus.
The formulas, exactly as the calculator runs them:
The amortised comparison (informational only)
To show the cost of paying everything in one month, the calculator also computes the alternative where the same bonus is spread evenly across all 12 months (one-twelfth added to each month's salary). This treatment has no statutory basis in Vietnamese payroll, but it is a clean way to reveal the bracket jump:
The penalty is always zero or positive: paying a bonus as one lump sum never costs less tax than spreading it, and usually costs more once the lump pushes you across a band line.
Parameters the calculator uses (2026 tax year)
All values are for the 2026 tax year and link to the authentic government text in Section 8. The 13th-month / Tet calculator reuses the same constants as the main PIT calculator, because a bonus is taxed on the same schedule.
- Personal deduction: 15,500,000 VND / month · subtracted before tax · Resolution 110/2025/UBTVQH15
- Per-dependant deduction: 6,200,000 VND / month each · subtracted before tax · Resolution 110/2025/UBTVQH15
- Social insurance (BHXH): 8% of salary · salary only, bonus excluded · Law 41/2024/QH15 Art. 33
- Health insurance (BHYT): 1.5% of salary · salary only, bonus excluded · Health Insurance Law 25/2008 as amended by 51/2024/QH15
- Unemployment insurance (BHTN): 1% of salary · salary only, bonus excluded · Employment Law 74/2025/QH15
- BHXH + BHYT base cap: 20 × reference level = 50,600,000 VND (from 1 Jul 2026) · caps the insurance base · Law 41/2024/QH15 Art. 31.1.d
- BHTN base cap: 20 × zone minimum wage (Zone I: 106,200,000 VND) · caps the insurance base · Employment Law 74/2025/QH15 Art. 34.2
- Reference level: 2,530,000 VND (from 1 Jul 2026 per Decree 161/2026/ND-CP; 2,340,000 before) · sets the BHXH+BHYT cap · Decree 73/2024/ND-CP; Decree 161/2026/ND-CP
- Zone I / II / III / IV minimum wage: 5,310,000 / 4,730,000 / 4,140,000 / 3,700,000 VND · sets the BHTN cap · Decree 293/2025/ND-CP
The progressive bands (kept brief)
The bands are the standard 2026 PIT schedule applied to monthly taxable income: 5% up to 10 million, 10% to 30 million, 20% to 60 million, 30% to 100 million, and 35% above 100 million (Law 109/2025/QH15 Article 9). For bonuses, the band detail matters only because the lump sum can reach into the higher bands in one month. The worked examples below show the band-by-band split so you can verify the result; for the full progressive treatment of regular salary, see the Personal Income Tax calculator.
3. Why the lump-sum bracket jump costs you
Paragraph repeated as a heading so the single most-searched idea stands alone: why does my Tet bonus get taxed so heavily?
The bonus itself is not taxed at a special rate. The issue is timing. Because PIT is calculated month by month on a progressive scale, dropping a large bonus into one month stacks it on top of that month's salary and pushes the combined total across one or more band lines. Income that would have sat in the 5% or 10% band if it had been spread out instead gets taxed at 20%, 30%, or even 35% in the bonus month.
Spreading the same amount over 12 months keeps each month nearer the bottom of the scale, so more of it is taxed at the lower bands. The difference between the two, the bracket-jump penalty, is what the comparison panel in the calculator shows. The bigger the bonus relative to your salary, and the closer your salary already sits to a band line, the larger the penalty. For small bonuses on modest salaries the penalty can be zero, because even the combined month stays inside a single band.
4. Worked examples
Each example follows a named person through the full calculation. The figures are the exact output of the calculator above. We show the band-by-band split for the bonus month so you can check the arithmetic, and we compare the lump-sum result with the amortised (spread over 12 months) result so the bracket-jump penalty is visible.
Note on what 'tax on the bonus' means here. It is the extra PIT caused by the bonus, that is, the bonus-month tax minus a normal month's tax. It is not the whole month's tax bill. This is the honest way to isolate what the bonus alone costs you.
Example A: a junior accountant in Ha Noi gets a one-month Tet bonus
Mai is a junior accountant in Ha Noi earning 18,000,000 VND (18 million) a month with one dependant, her younger brother. Her company pays a Tet bonus equal to one month's salary, so 18,000,000 VND, all in the January payroll. She works in Zone I and is a tax resident.
Inputs: salary 18,000,000 VND/month · bonus 18,000,000 VND · 1 dependant · Zone I · tax resident
Of her 18,000,000 bonus, Mai keeps 17,259,000 VND. The lump-sum bracket-jump penalty versus spreading it over 12 months is 741,000 VND (about 4.1% of the bonus).
Basis: Law 109/2025/QH15 Art. 9 (Bands 1 and 2); Resolution 110/2025/UBTVQH15 (deductions); bonus excluded from insurance per Law 41/2024/QH15 Art. 31.1.d.
Example B: a department head in Ho Chi Minh City gets a two-month bonus
Hung heads a department in Ho Chi Minh City and earns 40,000,000 VND (40 million) a month with two dependants, his two children. His firm has had a strong year and pays a Tet bonus of two months' salary, 80,000,000 VND (80 million), in one payment. Zone I, tax resident.
Inputs: salary 40,000,000 VND/month · bonus 80,000,000 VND · 2 dependants · Zone I · tax resident
As a lump sum, Hung keeps 63,525,000 VND of his 80,000,000 bonus; amortised he would keep 73,260,000. The bracket-jump penalty is 9,735,000 VND (about 12.2% of the bonus). The lump payment pushes him from the 5% band into the 30% band for one month, which is what makes the difference so large.
Basis: Law 109/2025/QH15 Art. 9 (Bands 1 to 4); Law 41/2024/QH15 Art. 31.1.d (bonus excluded from insurance; 40M salary below the 50.6M cap).
Example C: a single engineer in Da Nang gets a half-year bonus
Tuan is a software engineer in Da Nang earning 30,000,000 VND (30 million) a month with no dependants. His company pays a year-end bonus of 60,000,000 VND (60 million) in one payment. He works in Zone II, where the minimum wage is 4,730,000, and is a tax resident.
Inputs: salary 30,000,000 VND/month · bonus 60,000,000 VND · 0 dependants · Zone II · tax resident
As a lump sum, Tuan keeps 48,730,000 VND of his 60,000,000 bonus; amortised he would keep 54,000,000. The bracket-jump penalty is 5,270,000 VND (about 8.8% of the bonus).
Basis: Law 109/2025/QH15 Art. 9 (Bands 1 to 4); Decree 293/2025/ND-CP (Zone II minimum wage); Law 41/2024/QH15 Art. 31.1.d (bonus excluded from insurance).
5. Frequently asked questions
Is a Tet bonus taxable in Vietnam?
Yes. A Tet bonus (thưởng Tết) and a 13th-month salary are taxed as ordinary employment income under Personal Income Tax Law 109/2025/QH15. The whole bonus is added to your salary in the month it is paid and taxed on the progressive 5% to 35% bands. There is no separate, lower "bonus tax" rate and no tax-free allowance specific to bonuses. The only relief is that the bonus is excluded from social, health, and unemployment insurance, so no 10.5% insurance is taken from it.
How is tax on a 13th-month salary calculated?
The 13th-month payment is stacked on top of your normal salary in the month it lands. Your insurance and family deductions are subtracted (insurance is computed on salary only, not on the bonus), and PIT is applied to the combined taxable income on the progressive bands. The tax attributable to the bonus is that month's tax minus what an ordinary month would have cost. Because the bonus sits on top of your salary, it is taxed at your highest applicable band, which is often higher than your salary alone would reach.
How can I avoid the bracket jump on my Tet bonus?
The lawful way to soften it is for the employer to spread the bonus across several months rather than pay it all at once, so each month stays nearer the lower bands. The calculator's amortised comparison shows the saving: in the worked examples it ranges from about 4% to 12% of the bonus. This is an employer payroll-design choice, not something an employee can do unilaterally, and the bonus is still fully taxable either way. Splitting a payment purely to dodge tax can also raise questions at finalisation, so it should reflect a genuine pay arrangement.
Does a Tet bonus have social insurance (BHXH) deducted?
No. A 13th-month salary, Tet bonus, and performance or KPI bonuses are excluded from the social-insurance contribution base (Social Insurance Law 41/2024/QH15 Article 31.1.d, with the exclusion confirmed by Circular 06/2021/TT-BLDTBXH Article 3 and Official Letters 560/LDTBXH-BHXH and 1198/CTL&BHXH-BHXH). Your BHXH 8%, BHYT 1.5%, and BHTN 1% are charged only on your labour-contract salary, so they are identical in the bonus month and in every other month. Only your PIT changes when the bonus is paid.
What is the difference between a 13th-month salary and a Tet bonus, for tax?
For tax there is no difference: both are employment income taxed on the same progressive bands and both are excluded from insurance. The distinction is contractual. A 13th-month salary (lương tháng 13) is usually a fixed extra month written into the pay arrangement, while a Tet bonus (thưởng Tết) is discretionary and often tied to company results or individual KPIs (Labour Code 45/2019/QH14 Article 104 defines a bonus broadly as money, property, or other forms based on results). The calculator treats any year-end lump sum the same way.
Why is the tax on my bonus higher than the tax on my salary?
Because of progressive banding and timing, not a special rate. Your salary is taxed band by band starting from 5%, but the bonus is added on top of your salary, so it is taxed in your highest bands. If your salary already uses up the 5% and 10% bands, the bonus can be taxed at 20%, 30%, or 35%. Paying the whole bonus in one month maximises this effect. The "tax on the bonus" figure in the calculator is the extra tax the bonus causes, which is why it looks like a high rate compared with your salary's average rate.
Are small bonuses ever tax-free?
Effectively yes, when the bonus month still falls below your tax-free threshold. If your salary after insurance and deductions is already low or negative (common for modest salaries with dependants), a small bonus may not push the combined month into a taxable range, so the bracket-jump penalty is zero. For example, a worker on 12,000,000 a month with two dependants who receives a 12,000,000 bonus stays below the threshold even in the bonus month and pays no PIT on it. The calculator shows a zero penalty in those cases.
When are the 2026 bonus rules in effect, and do mid-year changes matter?
These figures apply for the 2026 tax year. The personal deduction (15,500,000) and dependant deduction (6,200,000) under Resolution 110/2025/UBTVQH15 apply across 2026, and the 2026 progressive bands under Law 109/2025/QH15 Article 9 govern the bonus. The reference level behind the insurance cap rose from 2,340,000 to 2,530,000 on 1 July 2026 (Decree 161/2026/ND-CP), lifting the BHXH + BHYT cap to 50,600,000 — this nudges the insurance of high earners, but because bonuses are not insured this change does not affect the tax on the bonus itself, only the regular salary side.
6. Common scenarios and edge cases
- Bonus paid across two pay periods. If a company splits the bonus over, say, December and January payrolls, each instalment stacks only on that month's salary. The calculator models a single lump payment; two smaller payments will usually carry a smaller combined penalty than one large one. The amortised line is the limiting case of spreading it across all 12 months.
- Very large bonus relative to salary. When the bonus is several times the monthly salary (as in Example B), the bonus month can reach the 30% or 35% band even if the salary alone never leaves the 5% band. This is where the lump-sum penalty is largest, often 10% or more of the bonus.
- Salary above the insurance cap (over 50,600,000). Social and health insurance freeze at 8% and 1.5% of 50,600,000, while unemployment insurance keeps scaling on salary up to 20 times the zone minimum wage. Either way the bonus is still excluded from insurance, so only the regular-salary insurance figure changes; the bonus tax is computed the same way.
- No dependants. Only the 15,500,000 personal deduction applies, so the normal-month taxable income is higher and the bonus more easily reaches the upper bands (see Example C).
- Modest bonus, low salary. If the combined bonus month stays inside one band, there is no bracket jump and the penalty is zero. The bonus is still taxed, but at the same low rate as the salary it sits on.
- Multiple employers. The calculator assumes a single labour contract. If you receive bonuses from more than one employer, each withholds separately and the totals are reconciled at the annual PIT finalisation, which can change the final figure.
7. Key terms
8. Legal basis and sources
Every figure on this page traces to the primary Vietnamese legal text. Links go primarily to the National Legal Portal (phapluat.gov.vn), the Ministry of Justice portal HAPRI uses as its source of record, with a full-text link to the Ministry of Justice National Legal Database (vbpl.vn) alongside for the complete machine-readable text.
9. Methodology, scope and disclaimer
This page and the calculator above model the 2026 tax year treatment of a 13th-month salary or Tet bonus for the common employee case: a resident or foreign worker on a single labour contract whose bonus is paid as a one-off lump sum. The lump-sum method is the standard Vietnamese payroll practice and the calculator's default; the amortised (spread over 12 months) figure is provided only to illustrate the bracket-jump penalty and has no statutory basis.
The tool does not model business income, capital gains, securities or real-estate transfers, royalties, inheritance, gifts, or lottery winnings, and it assumes one employer. It assumes the bonus is excluded from the social-insurance base, which is correct for 13th-month salary and Tet / KPI bonuses but may differ for fixed, regular supplements written into the contract.
The calculator is an estimation aid, not professional tax advice. For a formal filing or a bonus-structuring decision, consult a licensed Vietnamese tax practitioner or the General Department of Taxation (Tổng cục Thuế). HAPRI is an independent research institute and has no commercial interest in your result; the tool is free and the full methodology is published so you can audit every number.
10. About this calculator
HAPRI (the Health and Agricultural Policy Research Institute) builds free, openly-documented tools to make Vietnamese public policy legible to the people it affects. This 13th-Month / Tet Bonus calculator is part of a suite of seven covering personal income tax, take-home pay, pensions, and social insurance. The math is version-controlled, tested against the primary law, and refreshed from a live constants database, so the figures here stay in step with the statute as it changes. Because a bonus is taxed on the same schedule as salary, this calculator shares its constants with the Personal Income Tax calculator, and a change to the law updates both at once.
11. Related HAPRI calculators
- Personal Income Tax calculator — monthly personal income tax under the 2026 five-band schedule (Law 109/2025/QH15).
- Gross-to-Net Salary calculator — turn a contract gross salary into the monthly take-home pay you actually receive.
- Net-to-Gross (gross-up) calculator — work back from a target take-home figure to the gross an employer must offer.
- Pension calculator — your monthly retirement pension under Social Insurance Law 41/2024/QH15.
- Lump-Sum Social Insurance (BHXH) calculator — a one-time social-insurance (BHXH) withdrawal versus waiting for a monthly pension.
- Unemployment Insurance calculator — the monthly jobseeker benefit and how many months it lasts.