Sources & methodology
CobraCalc is built on public 2026 rules. This page shows exactly where each number comes from and how the math is done, with links to the official sources. We want you to be able to check our work.
What CobraCalc calculates
CobraCalc compares two ways to pay for health insurance after you retire early, for each year from the year you leave your job through age 64:
- COBRA — keeping your old employer plan at full price, offered for up to 18 months.
- The ACA Marketplace — a Silver plan whose price can be lowered by an income-based subsidy.
For each year it estimates your income compared to the poverty line, the price of a benchmark Silver plan for your age, the share of income you are expected to pay, and the subsidy that fills the gap. Then it picks the cheaper path. At age 65, Medicare takes over and the comparison ends. All the math runs in your browser; nothing you type is sent to a server.
Poverty guidelines (FPL)
Your subsidy depends on your income as a percent of the Federal Poverty Level (FPL) for your household size. CobraCalc uses the 2025 HHS poverty guidelines, because 2026 Marketplace subsidies are figured using the prior year's guidelines. For the lower 48 states:
| Household size | 2025 poverty guideline |
|---|---|
| 1 person | $15,650 |
| 2 people | $21,150 |
| 3 people | $26,650 |
| 4 people | $32,150 |
| Each extra person | +$5,500 |
Your FPL percent = MAGI ÷ poverty guideline for your household size × 100.
Source: HHS / ASPE Poverty Guidelines.
The 2026 subsidy percentage table
The "applicable percentage" is the share of your income you are expected to pay toward the benchmark plan. The subsidy covers the rest. For 2026, this table reverts to the original sliding scale, because the enhanced ARPA/IRA subsidies expired on December 31, 2025.
The scale runs from about 2.10% of income (at roughly 150% of the poverty line and below) up to about 9.96% of income near 400% of the poverty line. Above 400% FPL there is a hard cliff: no subsidy at all. CobraCalc slides smoothly between the rows of the table rather than jumping.
Source: IRS Revenue Procedure 2025-25.
Age-rated benchmark Silver premium
Marketplace premiums are age-rated: an insurer can charge the oldest adults up to 3 times what it charges the youngest adults (a 3:1 ratio). CobraCalc uses the federal default age curve to scale the benchmark price by your age.
Source: CMS market rating rules and Default Age Curve.
For the starting price, CobraCalc uses a national-average benchmark Silver premium of about $625 per month at age 40 for 2026 (source: KFF State Health Facts), then multiplies it by the age factor for your age. This is a national average, not your state's actual rate. Real prices vary widely by state and even by county, so for the most accurate result you can enter a real local quote for your age in the assumptions box.
Social Security and MAGI
Subsidies are based on your Modified Adjusted Gross Income (MAGI). One detail trips many people up: for ACA MAGI, you count the full Social Security benefit — including the part that is not taxed on your federal return. This can push your income higher than you expect once benefits start.
Source: HealthCare.gov MAGI / income definition.
Coverage decisions end at age 65, when most people become eligible for Medicare. That is why CobraCalc stops the COBRA-vs-Marketplace comparison at 64. Source: Medicare.gov.
How often we update
The numbers above are tied to a specific year. The poverty guidelines, the applicable-percentage table, and the benchmark premium all change yearly. We review the figures each year when the new IRS revenue procedure and HHS guidelines are published, and update the calculator and this page together. The "last reviewed" date below tells you when we last checked.
What this tool can't do
CobraCalc gives an estimate to help you plan. It is not a real quote or a guarantee. A few honest limits:
- National-average premium. The starting Silver price is a national average, not your state's rate. Prices vary a lot by state and county. State-specific pricing is a planned future upgrade; for now, enter a real local quote for the closest result.
- Simplified Medicaid treatment. Income below 100% of the poverty line is flagged as "likely Medicaid." Real Medicaid expansion typically uses a 138% FPL threshold and the rules vary by state, so treat this flag as a prompt to check your state, not a final answer.
- Tax law can change. The subsidy table, the cliff, and other rules are set by law and can be changed by Congress. We update when that happens, but always confirm current rules before a big decision.
Related guides
Last reviewed: June 2026.
This is an estimate to help you plan, not insurance or tax advice. See the disclaimer.