Your ACA health insurance subsidy—called the Premium Tax Credit—is calculated using a specific federal formula. This page walks through exactly how that formula works, what variables affect it, and how to estimate your own number.
The ACA Subsidy Formula
Subsidy = SLCSP Premium − (Your Income × Applicable %)
SLCSP = Second Lowest Cost Silver Plan in your county
There are two moving parts in this formula: the SLCSP premium (which varies by your age and location) and your applicable contribution percentage (which is set by the government based on your income). Understanding both is the key to understanding your subsidy.
The Second Lowest Cost Silver Plan (SLCSP) is the government’s benchmark plan for your area. The subsidy is always calculated against this benchmark—not whatever plan you actually enroll in. Two things affect the SLCSP premium:
Note on Gender
The ACA prohibits gender rating for individual market plans. Gender does not affect your premium or your subsidy—this has been the rule since 2014.
The government sets a sliding scale for how much of your income you’re expected to contribute toward the benchmark plan. This percentage is based on your income as a percentage of the Federal Poverty Level (FPL). The lower your income relative to the FPL, the lower your expected contribution.
For 2026, the contribution percentages increased significantly compared to 2021–2025, and eligibility is now capped at 400% FPL (the “subsidy cliff” returned):
| Annual Income (1 Person) | % of FPL | Max % of Income for Benchmark Plan |
|---|---|---|
| Up to $21,227 | Under 133% | 2.10% |
| $21,228 – $23,940 | 133% – 150% | 3.14% – 4.19% |
| $23,941 – $31,920 | 150% – 200% | 4.19% – 6.60% |
| $31,921 – $39,900 | 200% – 250% | 6.60% – 8.44% |
| $39,901 – $47,880 | 250% – 300% | 8.44% – 9.96% |
| $47,881 – $63,840 | 300% – 400% | 9.96% |
| Over $63,840 | Over 400% | No subsidy — full premium |
Income thresholds based on 2026 Utah FPL of $15,960 for one person. Source: IRS Rev. Proc. 2025-25. For other household sizes, divide your income by your household’s FPL.
Step 1: Find your MAGI. Your Modified Adjusted Gross Income is the income figure used for subsidy eligibility. For most people this is close to your household’s total gross income. It includes wages, self-employment income, Social Security, and investment income. It does not include certain deductions like pre-tax 401(k) contributions.
Step 2: Calculate your FPL%. Divide your MAGI by the FPL for your household size. In 2026, the FPL is $15,960 for one person in Utah (same as the rest of the 48 contiguous states). For a household of 4, it’s $33,000.
Step 3: Look up your contribution %. Use the table above to find your income bracket and applicable percentage range.
Step 4: Find the SLCSP premium for your situation. You can find this by running a quote at your actual age and zip code. Because this number varies by age and county, this is where two people with identical incomes can end up with very different subsidies.
Step 5: Subtract. Subsidy = SLCSP Premium − (Your MAGI × Contribution %). If the result is negative (your expected contribution exceeds the SLCSP premium), your subsidy is $0.
Here’s a concrete example using a 40-year-old individual in Salt Lake County with a $38,000 annual income:
| Variable | Amount |
|---|---|
| Your annual income (MAGI) | $38,000 |
| 2026 FPL for 1 person in Utah | $15,960 |
| Your FPL% | 238% ($38,000 ÷ $15,960) |
| Applicable contribution % | ~7.8% (within the 200–250% bracket) |
| Your expected annual contribution | $2,964 ($38,000 × 7.8%) |
| Your expected monthly contribution | ~$247/mo |
| SLCSP premium (example: 40-yr-old, Salt Lake Co.) | ~$450/mo |
| Your monthly subsidy | ~$203/mo ($450 − $247) |
This person would receive approximately $203/month in advance premium tax credit (APTC).
Your subsidy is fixed based on the SLCSP. You can apply it to any metal-tier plan. If you choose a plan cheaper than the SLCSP, you pocket the difference (down to $0). If you choose a more expensive plan, you pay 100% of the gap above the SLCSP out of your own pocket.
Using the example above ($203/month subsidy):
| Plan Type | Full Premium | Your Cost After $203 Subsidy |
|---|---|---|
| Bronze plan | $300/mo | $97/mo (you keep $150 in savings vs. SLCSP) |
| Silver (SLCSP benchmark) | $450/mo | $247/mo |
| Gold plan | $560/mo | $357/mo (you pay 100% of the difference above SLCSP) |
In most states, insurers can add a tobacco surcharge of up to 50% to your premium. Utah follows federal rules, so this may apply. Importantly, your subsidy cannot be used to offset the tobacco surcharge—only the base premium is subsidizable. Tobacco users may end up paying significantly more even with a full subsidy.
When you enroll, you estimate your income for the year. The government pays your subsidy upfront (as APTC) based on that estimate. At tax time, you compare your estimate to your actual income on Line 11 of your Form 1040 (your Adjusted Gross Income) using Form 8962:
If your income changes during the year—job change, raise, self-employment fluctuation—you can update your estimate in your marketplace account to avoid a large reconciliation surprise. If you’ve had a qualifying life event like a job change or move, you may also be eligible for a Special Enrollment Period.
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