Health Insurance Terms

ACA (Affordable Care Act)

The Affordable Care Act (ACA), also known as Obamacare, is a comprehensive US healthcare reform law signed into law in 2010. It aims to increase access to affordable health insurance, improve healthcare quality, and reduce healthcare costs for individuals and families.

Definition maintained by the InsurTool Editorial Team. Last reviewed .

Key Takeaways

  • The ACA (Affordable Care Act), also known as Obamacare, was signed into law in 2010
  • It established health insurance marketplaces for individuals to purchase coverage
  • Insurance companies cannot deny coverage due to pre-existing conditions
  • Premium tax credits and cost-sharing reductions are available for eligible individuals
  • All plans must cover 10 essential health benefits
  • Use our Health Insurance Calculator to see if you qualify for subsidies

What is the Affordable Care Act (ACA)?

In plain English: The Affordable Care Act (ACA), also called “Obamacare,” is the U.S. federal law passed in 2010 that reformed health insurance. It created health insurance marketplaces, expanded Medicaid, required insurers to cover essential health benefits, and prevented insurers from denying coverage or charging more for pre-existing conditions.

The ACA represents one of the most notable changes to the US healthcare system in decades, with the goal of making health insurance more accessible and affordable for all Americans.

How the ACA Works

Health Insurance Marketplaces

The ACA established health insurance marketplaces (exchanges) where individuals and small businesses can compare and purchase health insurance plans. These marketplaces are available online, by phone, and in person through navigators and assisters.

Financial Assistance

The ACA provides two types of financial assistance to help make insurance more affordable:

  • Premium Tax Credits: Lower your monthly premium costs based on your income
  • Cost-Sharing Reductions: Lower your deductibles, copays, and coinsurance
Plan Type Provider Choice Referral Needed? Premium Level
HMO In-network only Yes Lower
PPO In & out of network No Higher
EPO In-network only No Medium
POS In & out of network Yes for specialists Medium

Key Provisions

  • Health Insurance Marketplace — Online platforms where individuals can shop for health insurance.
  • Premium Tax Credits — Financial assistance to lower monthly premium costs.
  • Cost-Sharing Reductions — Help lower deductibles, copays, and coinsurance.
  • Guaranteed Issue — Insurance companies can’t deny coverage due to pre-existing conditions.

Essential Health Benefits

All ACA-compliant health insurance plans must cover these 10 essential health benefits:

  • Ambulatory patient services: Outpatient care
  • Emergency services: Emergency room visits
  • Hospitalization: Inpatient care
  • Maternity and newborn care: Prenatal and postnatal care
  • Mental health and substance use disorder services: Counseling and treatment
  • Prescription drugs: Medications
  • Rehabilitative and habilitative services: Physical therapy, speech therapy
  • Laboratory services: Diagnostic tests
  • Preventive and wellness services: Vaccinations, screenings
  • Pediatric services: Children’s health care

Open Enrollment

The ACA established an annual open enrollment period during which individuals can purchase or change health insurance plans through the marketplace. Outside of open enrollment, you may qualify for a special enrollment period if you experience a qualifying life event such as losing job-based coverage, getting married, or having a baby.

Calculate Your ACA Eligibility

Not sure if you qualify for ACA subsidies or what your costs would be? Try our Health Insurance Calculator to estimate your premium tax credits and compare plan options.

Frequently Asked Questions (FAQ)

Q: Is the ACA still in effect?

A: Yes, the Affordable Care Act is still in effect. While some provisions have been modified over the years, the core structure remains intact.

Q: What is Obamacare?

A: Obamacare is the informal name for the Affordable Care Act (ACA), named after President Barack Obama who signed it into law.

Q: Can I be denied health insurance because of a pre-existing condition?

A: No, under the ACA’s guaranteed issue provision, insurance companies cannot deny coverage or charge more based on pre-existing conditions.

Q: How do I sign up for ACA coverage?

A: You can sign up through the Healthcare.gov marketplace, or through your state’s marketplace during open enrollment or a special enrollment period.

Authority Sources

Health Insurance Copay Coinsurance Medicare Medicaid

About this definition

Written and checked against the primary sources linked on this page by the InsurTool Editorial Team. Definitions describe how these terms are used in the United States; policy wording differs between insurers, and state law changes the meaning of some terms. Your own policy document is the authority for your coverage.

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InsurTool·Reviewed by Alice Zhang

Figures on this page are compiled by the InsurTool editorial team from NAIC and state Department of Insurance publications, the Insurance Information Institute, and carrier methodology disclosures. Every figure is checked against its cited source before publication; anything unverified is labelled as an estimate or left out. InsurTool is an educational resource — not insurance, brokerage, or financial advice.