Methodology
BenefitGap Plan translates one 2026 SSA Trustees Report figure into a transparent arithmetic example. OASI continuing income would pay 78% of scheduled benefits at 2032-Q4 depletion, leaving a 22% planning gap. This page shows the monthly and annualized arithmetic. The result is a static hypothetical scenario, not an SSA forecast or enacted cut.
Source: 2026 SSA Trustees Report, reviewed November 2026
dateModified: November 2026 · Reviewed November 2026
The formula, step by step
The calculator first asks which benefit type the amount describes. The official 22% OASI reference scenario is available for OASI retirement and survivors benefits. The user enters a gross monthly benefit as a current amount or a nominal future estimate, together with known fixed deductions. The calculator accepts dollars and cents, strips formatting characters, and stores the amount as an integer number of cents. That step avoids binary floating-point drift when the same amount is multiplied, subtracted, and displayed several times.
Next, the selected scenario percentage is converted to basis points. A percentage is multiplied by 100; for example, 22% becomes 2200 basis points out of 10,000. The monthly difference is the gross monthly benefit in cents multiplied by those basis points and divided by 10,000, rounded once to the nearest whole cent. The modeled payable amount is the original gross benefit minus that monthly difference. The annualized difference is the monthly difference multiplied by 12; it is a simple planning scale-up of one month's selected rate, not a claim about the actual number of payments affected during calendar year 2032.
If fixed deductions are known, the calculator subtracts them from the modeled payable amount to show a net monthly benefit. If deductions are unknown, it does not assume they are zero; it suppresses net and household-budget conclusions and labels the gross-only result. If the modeled payable amount is smaller than the deductions entered, the net result is withheld rather than shown as a misleading negative benefit. Optional budget fields add other net income, essential expenses, and flexible expenses. Those fields are integer cents too. The current and scenario balances are sums and subtractions of the entered amounts; no inflation adjustment or future-dollar conversion is performed.
Integer rounding and the shared calculation
Every monetary input is parsed as an integer number of cents. A blank field is treated as unknown, while an explicit 0 is treated as zero. Amounts may have at most two decimal places; values that are not finite, are negative, exceed the calculator's safe input bounds, or cannot be represented as safe integers are rejected. Deductions may not exceed the entered gross monthly benefit. Scenario rates must be between 0% and 100% and may use at most two decimal places when expressed as a percentage.
The only percentage multiplication uses the calculator's shared integer-rounding rule: add half the divisor, take the floor of the quotient, and keep the result in whole cents. This is equivalent to rounding a non-negative cent amount to the nearest cent, with exact halves rounded up. The same shared computation produces the live calculator result and the example table below. A second copy of the percentage mathematics is deliberately not implemented on this page or elsewhere. Display formatting converts cents back to dollars only after the arithmetic is complete, using U.S. currency formatting.
Rounding is applied once to the monthly difference, not separately to a gross amount, a net amount, and an annual amount. The payable amount is then derived by subtraction, and the annualized figure is derived by multiplying the already-rounded monthly difference. This keeps the displayed rows internally consistent. The calculator may also accept custom hypothetical rates for sensitivity testing, but a custom rate is labeled as custom; it is not presented as a figure from the Trustees Report.
Amount checks using the 78% payable share
The table below is generated by calling the same calculator routine used in the interactive tool. It tests four whole-dollar monthly benefits. At a 22% difference, the modeled amounts payable at 78% are $936, $1,404, $1,872, and $2,340. The corresponding monthly differences are $264, $396, $528, and $660. Multiplying each monthly difference by 12 gives annualized differences of $3,168, $4,752, $6,336, and $7,920. These are arithmetic illustrations of one selected rate applied for twelve identical months; they are not SSA benefit determinations and not forecasts for a particular year.
| Current monthly benefit | Payable at 78% | Monthly difference | Annualized difference |
|---|---|---|---|
| $1,200.00 | $936.00 | $264.00 | $3,168.00 |
| $1,800.00 | $1,404.00 | $396.00 | $4,752.00 |
| $2,400.00 | $1,872.00 | $528.00 | $6,336.00 |
| $3,000.00 | $2,340.00 | $660.00 | $7,920.00 |
Source: 2026 SSA Trustees Report, reviewed November 2026
Section II.A, Table II.A1 reports 78% payable upon OASI reserve depletion. Each row is an arithmetic illustration produced with the calculator's shared integer-cent logic, not an individual SSA benefit estimate.
For example, $1,200 is stored as 120,000 cents. The 22% reference is 2,200 basis points. Multiplying 120,000 by 2,200 and dividing by 10,000 produces 26,400 cents, or $264. Subtracting that from 120,000 cents gives 93,600 cents, or $936. The other rows follow the same shared operation. Because these examples use whole-dollar inputs at a whole-percent rate, the results are exact whole dollars; the integer-cent rounding rule matters for inputs that include cents or custom rates with basis-point precision.
Assumptions and boundaries
The official reference scenario uses the 2026 Trustees Report's intermediate assumptions and the separate OASI Trust Fund basis. The report's 78% payable share describes continuing income at reserve depletion under current-law financing; the 22% complement is a financing gap, not an enacted universal benefit reduction. The calculator does not predict cost-of-living adjustments, federal or state taxes, Medicare premiums or other deductions, changes in eligibility, claiming behavior, earnings history, legislation, litigation, or an individual's actual 2032 losses. It also does not forecast what a later annual Trustees Report will project.
A nominal future amount entered by a user is flagged as such; the calculator does not convert it to real purchasing power or apply an assumed inflation path. A custom percentage is a what-if input and has no official source status. The annualized line assumes twelve months at the selected rate for easy comparison with annual budget categories; depletion in the fourth quarter of 2032 means that it is explicitly not a full-year 2032 loss estimate. The tool also does not model investment returns, annuity income, debt strategy, tax filing status, spousal coordination, or an optimal claiming age.
When this method does not apply
Do not use the 22% OASI reference as an SSDI payment forecast. The 2026 Trustees Report projects that DI reserves remain sufficient to pay full scheduled benefits throughout the 75-year projection period, and Section II.A reports 100% payable for DI before reserve depletion with no projected depletion date. Do not use an OASI or OASDI trust-fund depletion date for SSI: the Section VI.I Glossary explains that the General Fund of the Treasury funds federal SSI expenditures. If a household receives both Social Security and SSI, confirm the source of each payment before entering an amount. For mixed or uncertain benefit types, the calculator asks the user to confirm the type with SSA before relying on a result.
Source: 2026 SSA Trustees Report, reviewed November 2026
The separate OASI calculation also should not be combined with the hypothetical combined OASDI projection. The separate-fund report basis gives 2032-Q4 and 78% payable; a combined presentation gives 2034-Q3 and 83% payable only under the assumption that the legally separate funds could be used together. Adding the two shortfalls would invent a number absent from the report. Read why the 2032 and 2034 projections differ before comparing those bases, or use the 2032 benefit calculator for a single transparent OASI scenario.
Official report sections
The figures and boundaries on this page come from distinct sections of the 2026 SSA Trustees Report and official SSA material. Section II.A and Table II.A1 provide the key results; Section II.D explains the quarter-level projections; Section II.E clarifies the legal assumption behind a combined presentation; Section IV.B defines the long-range measures; Section VI.I distinguishes SSI's funding; and the Trustees Report Summary restates the projections. The SSA press release offers an additional official cross-check. Each link below opens a separate official source.
- 2026 Trustees Report, Section II.A — Highlights and Table II.A1
- 2026 Trustees Report Summary — What Is Projected
- 2026 Trustees Report, Section II.D — Projections of Future Financial Status
- 2026 Trustees Report, Section IV.B — Long-Range Estimates
- 2026 Trustees Report, Section II.E — Conclusion
- SSA — Supplemental Security Income (SSI)
- SSA press release — 2026 Trustees Report projection
BenefitGap Plan is an independent educational tool and is not affiliated with or endorsed by the Social Security Administration.