This page documents how the cobravsaca.com estimator turns a few inputs into a COBRA vs. Marketplace comparison for 2026. It is the specification behind the JavaScript on the home page. If a result looks surprising, this is the first place to look — before assuming the code “gave you Medicaid” or “invented a ZIP premium.”
Inputs
You enter state (used only for a simplified Medicaid expansion flag), who needs coverage and their ages, a monthly COBRA premium (or an optional estimate from your old employee contribution), and expected annual household income. There is no ZIP field on purpose. We do not pretend to quote local silver premiums.
Federal poverty level (FPL)
Household MAGI is divided by the 2026 HHS poverty guideline for that household size in the 48 contiguous states and D.C. The table used in code is:
| Household size | 2026 FPL (contiguous states) |
|---|---|
| 1 | $15,960 |
| 2 | $21,640 |
| 3 | $27,320 |
| 4 | $33,000 |
| 5 | $38,680 |
| 6 | $44,360 |
| 7 | $50,040 |
| 8 | $55,720 |
| Each additional person | + $5,680 |
Alaska and Hawaii have higher guidelines. This calculator does not switch tables by state, which will slightly overstate FPL percentage (and can mis-place the 100% / 400% bands) for those two states. Treat results there as even rougher.
Household size in the tool is the number of age fields you add — the people you said need coverage. Official Marketplace household size for MAGI can include tax dependents who do not need coverage. If those differ, HealthCare.gov is the authority.
MAGI
We do not compute MAGI from a tax form. You type an expected annual figure. That should be household modified adjusted gross income for the coverage year: AGI plus items the Marketplace adds back (such as non-taxable Social Security and tax-exempt interest). After a job loss it should include unemployment compensation, severance, a spouse’s wages, and other remaining income — not last year’s salary alone. If you type a bad MAGI, every percentage after that is wrong. We do not reconcile Form 8962 for you.
Applicable percentages (2026 PTC)
Enhanced credits expired December 31, 2025. For 2026 we apply IRS Revenue Procedure 2025-25:
- Under 100% of FPL: no Marketplace premium tax credit (Medicaid or coverage gap depending on state).
- 100% to under 133%: 2.10% of MAGI toward the SLCSP.
- 133–150%: linear interpolation from 3.14% to 4.19%.
- 150–200%: 4.19% to 6.60%.
- 200–250%: 6.60% to 8.44%.
- 250–300%: 8.44% to 9.96%.
- 300–400%: 9.96%.
- Above 400%: no premium tax credit (the cliff).
Expected annual contribution is MAGI times that percentage. Monthly expected contribution is that amount divided by 12. The illustrated monthly credit is the illustrated SLCSP minus the expected contribution, floored at zero. If there is no credit, the Marketplace side shows the full illustrated SLCSP.
SLCSP national-average illustration
The second-lowest-cost silver plan is a local, age-rated premium. We do not have issuer rate filings by rating area. Instead we use a piecewise age curve as a 2026 national-average illustration (child rate under 21; then points from age 21 through 64). It is not a quote, not specific to your ZIP, and not an offer from any carrier. Actual silver premiums commonly land 20–40% above or below a national curve. Always replace this number with the SLCSP HealthCare.gov shows for your household.
Three-child ACA cap
When summing illustrated premiums, adults 21 and older are all counted. Children under 21 are counted up to three. Additional children under 21 add $0 to the illustrated SLCSP, which follows the ACA rating rule that family premiums include at most three children under 21. Children 21–25 who are on the application as adults are counted as adults in this simplification. Tobacco rating is omitted.
COBRA side and the 2% administrative fee
If you type a monthly COBRA premium, we use that number as-is for the COBRA column. That is the right input: the amount on the election notice, which already should include the employer share and the allowed administrative charge.
If you do not have the notice, the optional estimator takes the employee payroll contribution you remember and grosses it up using approximate average employee shares (about 15.3% for single coverage and 28.2% for family, in the range of recent KFF employer-survey averages) and then multiplies by 1.02 to add a 2% COBRA administrative fee. That estimate can be far from your employer’s actual contribution rate. Replace it with the notice as soon as it arrives. Federal COBRA permits up to 2% for administration (more in some disability extension cases). We do not model the 11% disability surcharge.
Medicaid expansion vs. coverage gap
Non-expansion states in this tool: Alabama, Florida, Georgia, Kansas, Mississippi, South Carolina, Tennessee, Texas, Wisconsin, and Wyoming. All other states plus D.C. are treated as expansion. If expansion and MAGI is under 138% of FPL, we flag likely Medicaid. If non-expansion and MAGI is under 100% of FPL, we flag a coverage gap (generally no adult Medicaid expansion and no Marketplace PTC). We do not evaluate pregnancy, disability, or parent categories. Select your actual state; we do not default every state to expansion.
What we still do not model
ZIP and rating area, tobacco, silver loading and CSR variation by FPL band on the plan design (we do not output a CSR silver deductible), employer affordability / MEC tests for people who still have an offer of coverage, state 1332 wrap subsidies, off-exchange plans, short-term policies, or Medicare. The recommendation text is a heuristic (Medicaid flag, then a savings threshold, then a toss-up band). It is not an optimization engine.
Related reading: How it works, 2026 subsidies, when COBRA vs. Marketplace wins.