Click here for the tool.
http://kff.org/interactive/subsidy-calculator/
"This tool illustrates health insurance premiums and subsidies for people purchasing insurance on their own in new health insurance exchanges (or “Marketplaces”) created by the Affordable Care Act (ACA). Beginning in October 2013, middle-income people under age 65, who are not eligible for coverage through their employer, Medicaid, or Medicare, can apply for tax credit subsidies available through state-based exchanges."