How the SSI federal rate is derived, and why the obvious method is wrong
Almost every calculator applies the cost-of-living adjustment to last year’s monthly SSI rate. That is not what SSA does, and for 2026 it produces a couple rate that is $1 a month too low.
2026 SSI federal rate, couple
$1,491
The naive monthly method gives $1,490. The difference is $1 a month, $12 a year.
- Individual
- $994both methods agree
- Couple, correct
- $1,491from the unrounded annual
- Couple, naive
- $1,490from the monthly rate
- Essential person
- $498
What SSA actually does
SSA carries an unrounded annual amount behind each published monthly rate. Each year the adjustment is applied to that annual figure and rounded to the cent; the monthly rate is the result divided by twelve and floored to the whole dollar. Crucially, the unrounded annual — not the floored monthly — is what seeds the following year, so the rounding never accumulates.
| Step | SSA’s method | The naive method |
|---|---|---|
| Starting figure | $17,404.87 a year | $1,450 a month |
| Apply 2.8% | $17,892.21 | $1,490.60 |
| Convert to a monthly figure | $1,491.02 | — |
| Floor to the whole dollar | $1,491 | $1,490 |
SSA publishes $1,491. The unrounded-annual method reproduces it exactly. The naive method is short by $1.
Why the error survives in the wild
Run the same comparison on the individual rate and both methods return $994 — $994 from the annual and $994 from the monthly. A developer checking their calculator against the individual rate sees agreement, ships, and never discovers that the couple rate is wrong. The error is invisible from the number most people test with.
The whole series, derived the same way
This is not a one-year quirk. This site reconstructs the entire published SSI series from the unrounded annuals and matches SSA’s published monthly rates year by year as a build gate — 52 years, with two era rules and one statutory override.
| Year | Individual | Couple | Unrounded annual, couple |
|---|---|---|---|
| 2026 | $994 | $1,491 | $17,892.21 |
| 2025 | $967 | $1,450 | $17,404.87 |
| 2024 | $943 | $1,415 | $16,980.36 |
| 2023 | $914 | $1,371 | $16,453.84 |
| 2022 | $841 | $1,261 | $15,136.93 |
| 2021 | $794 | $1,191 | $14,293.61 |
| 2020 | $783 | $1,175 | $14,110.18 |
| 2019 | $771 | $1,157 | $13,887.97 |
| 2018 | $750 | $1,125 | $13,509.70 |
| 2017 | $735 | $1,103 | $13,244.80 |
| 2016 | $733 | $1,100 | $13,205.18 |
| 2015 | $733 | $1,100 | $13,205.18 |
Two era rules and one override
- From 1984, the monthly rate floors to the whole dollar. Before that the statutory rates carried cents and floored to the dime — $284.30, $304.30 and so on. Applying today’s rule to those years gets them wrong.
- July 1983 was not an adjustment. SSA’s table shows an increase labelled 7.0% for 1983, which contradicts the fact that no cost-of-living adjustment was payable that year at all. P.L. 98-21 (Social Security Amendments of 1983) raised the federal rate by a flat $20.00 for an individual and $30.00 for a couple, in lieu of the adjustment it had just delayed. The arithmetic confirms it exactly: $284.30 plus $20.00 is $304.30, and $426.40 plus $30.00 is $456.40. No single percentage produces both. The 1983 page.
And one thing that is never done to an SSI payment
No Medicare Part B premium is deducted from it. SSI recipients are categorically Medicaid eligible in most states and the premium is paid by the state under a Medicare Savings Program buy-in. The engine behind this site refuses to apply a premium to an SSI amount rather than producing a plausible wrong number. The SSI figures in full.
Common questions
What is the unrounded annual amount?
A figure SSA carries at full precision behind the published monthly rate. Each year the adjustment is applied to the unrounded annual, and the monthly rate is that result divided by twelve and floored to the whole dollar. The unrounded annual is what seeds the next year, so the rounding never compounds.
Why does the individual rate agree under both methods?
Because the difference between the two methods is smaller than a dollar in most years, and the whole-dollar floor usually hides it. For 2026 the individual rate is $994 either way. The couple rate is where the difference crosses a dollar boundary and becomes visible.
How much does it actually matter?
$1 a month for a couple, $12 a year. Small in isolation, and it recurs every year and compounds into every downstream figure a site computes from it.
Did SSI ever get an increase that was not a COLA?
Yes, once, and SSA's own table labels it as a percentage. In July 1983 a statute raised the federal rate by a flat $20.00 for an individual and $30.00 for a couple, in lieu of the adjustment that had just been delayed from June to December.
Related
- The SSI seriesevery year
- SSI benefitsthe programme
- 1983the flat increase
- Methodologyrounding rules
- The 2026 COLA2.8%
- Student exclusionthe other SSI figure
Sources and freshness
- SSA OACT — SSI payment standards, 1975 and later — verified 10 August 2026
- SSA Office of the Chief Actuary — SSI federal payment amounts — verified 10 August 2026
- SSA Office of the Chief Actuary — Cost-of-Living Adjustments — verified 10 August 2026
Figures effective January 2026. Page figures last verified against the sources above on 10 August 2026. Corrections: the correction log · support@inventum.com.au