From 1995 until the end of last year, Thailand calculated social security contributions on a maximum wage of THB 15,000 a month. The figure did not move for thirty years. It moved on 1 January 2026, to THB 17,500.

If you are paid in Thailand and earn more than THB 15,000 a month, your January payslip showed a larger deduction than your December one. The most it can have grown by is THB 125.

The deduction is the obvious half. The less obvious half is what the same change does to your pension at the other end.

Who actually pays more

Contributions are 5% of your wage, but only the portion up to the ceiling is counted. Raising the ceiling therefore changes nothing at all for anyone earning below the old one:

monthly wage      before      from 2026     difference
THB 12,000        THB 600     THB 600       none
THB 15,000        THB 750     THB 750       none
THB 16,000        THB 750     THB 800       THB 50
THB 17,500        THB 750     THB 875       THB 125
THB 25,000        THB 750     THB 875       THB 125
THB 60,000        THB 750     THB 875       THB 125

Anyone under THB 15,000 a month pays exactly what they paid before, which much of the coverage has been vague about. And the increase is capped: THB 125 a month is the largest it gets, whether you earn THB 17,500 or ten times that.

Your employer matches whatever you pay, so the same THB 125 appears on their side too.

It happens again in 2029 and 2032

The regulation published in the Royal Gazette on 12 December 2025 did not set a new number. It set three of them:

1995-2025      ceiling THB 15,000     max THB 750/month
2026-2028      ceiling THB 17,500     max THB 875/month
2029-2031      ceiling THB 20,000     max THB 1,000/month
2032 onward    ceiling THB 23,000     max THB 1,150/month

The thirty-year freeze has been replaced by a three-yearly step. If you are budgeting employment costs past 2028, the numbers are already published.

What the extra THB 125 buys

The ceiling does two jobs, which is what makes this more of a purchase than a deduction. It caps what you pay in, and it caps the wage your pension is calculated from.

The old-age pension is 20% of your average covered wage over your last 60 months, once you have contributed for 180 months. Every further 12 months of contributions adds 1.5%.

Run the two ceilings through that formula:

last 60 months at THB 15,000     pension THB 3,000/month
last 60 months at THB 17,500     pension THB 3,500/month

THB 125 a month across the 60-month averaging window is THB 7,500 paid. It raises the pension by THB 500 a month, for life. You are square after fifteen months of retirement, and everything after that is the return.

As a deduction it is a pay cut. Run against the pension formula it is an automatic investment with a fifteen-month payback, and one of the better ones available to a Thai employee.

What it really costs, after tax

Social security contributions come off your taxable income, so the THB 125 is not quite THB 125. What it actually costs depends on the rate your last baht of income meets:

annual wage        marginal rate    extra per month, net
THB 216,000              0%              THB 125.00
THB 360,000              5%              THB 118.75
THB 600,000             10%              THB 112.50
THB 1,200,000           25%              THB  93.75
THB 2,400,000           30%              THB  87.50

The effect is not uniform. In gross terms the increase is flat, and everyone above the ceiling pays the same THB 125 whether they earn THB 18,000 a month or ten times that. After tax it is not flat at all: the same contribution costs a senior manager seventy satang in the baht of what it costs someone just over the line, for an identical pension.

The five-year window nobody mentions

That formula has a consequence most people miss: the pension is set by your last 60 months of contributions, not your career.

Contributions before that window get you to the 180-month qualifying threshold, and beyond that they do nothing for the size of the pension. Two people who both contributed for twenty years, one on a rising salary and one whose pay peaked early and drifted down, retire on very different pensions from very similar lifetime contributions.

It also means the higher ceiling does its work quickly. You do not need to have paid the new rate for thirty years to get the higher pension. You need it in the five years before you stop.

The number every calculator still shows

Search for Thai social security deductions and you will be told, repeatedly and confidently, that the maximum is THB 750 a month or THB 9,000 a year, and that THB 9,000 is the cap on what you may deduct from taxable income.

The first is simply last year's number. The second was never a rule. Social security contributions are deductible at the amount actually paid, with no separate statutory cap. The THB 9,000 figure was the old THB 750 monthly maximum multiplied by twelve: the ceiling in disguise. From 2026 the equivalent figure is THB 10,500.

This matters if you are filing: deducting THB 9,000 when you paid THB 10,500 understates your allowances and overstates your tax, by about THB 1,500 of taxable income.

A larger change is queued behind this one

A draft ministerial regulation proposes replacing the 60-month average with a career-average model that revalues earnings across a whole working life. It would also swap the 1.5%-per-year increment for a monthly calculation.

If it passes, the pension stops depending on your last five years, and a long career of steady contributions starts to count for what it actually was. It is awaiting review by the Council of State, so it is a thing to watch rather than a thing to plan around.

Where this comes from, and what will date

The ceilings and their dates are from the Ministerial Regulation published in the Royal Gazette on 12 December 2025, as reported by DLA Piper and BDO Thailand. The pension formula is the Social Security Office's. The tax treatment is from PwC's Worldwide Tax Summaries, which is also the source for the THB 60,000 personal allowance and the 50% employment deduction capped at THB 100,000. Read on 29 August 2026.

The arithmetic assumes you stay at or above the ceiling. Every figure above is what happens to someone whose wage is above THB 17,500 for the whole period in question. Careers are not like that, and a wage that crosses the ceiling partway through gives smaller numbers than these.

The pension figures are the formula, not a forecast. They are what the current rule produces for a given covered wage. They are not adjusted for inflation over the decades between contributing and collecting, and THB 3,500 in the 2050s is not THB 3,500 today.

This is Section 33 — ordinary employees. Section 39 for people who have left insured employment and Section 40 for informal workers have their own rates and their own ceilings, and none of the figures here transfer to them.

The Revenue Department's own English pages are behind. At the time of reading, they still showed a THB 30,000 personal allowance and a top bracket starting at THB 4 million, both superseded. That is a reason to check any Thai tax figure against a source that dates itself, including this one.