After years of often bitter debate, health care reform--a.k.a. the Affordable Care Act, or if you prefer, Obamacare--will take full effect January 1, 2014. How will it affect your company? Good question. Like Tolstoy's unhappy families, every business will be made unhappy in a different way by the new law.

Or maybe not: For smaller companies, it could mean subsidies that make offering health benefits more affordable. Companies with 50 or more full-time employees, on the other hand, could face a range of penalties for failing to offer affordable coverage.

Most employers will not have to make big changes. According to the Kaiser Family Foundation, 94 percent of businesses that employ 50 to 199 workers already offer benefits. And a survey by Towers Watson estimates that employers paid an average of 76 percent of employees' total health costs in 2012--above the 60 percent threshold mandated by the ACA.

But no one knows exactly how much Obama care will affect premiums, which surged 97 percent from 2002 to 2012. The law's new mandates--such as requiring insurers to cover preventive care at 100 percent--could drive rates higher. And small employers that buy insurance through the newly created Small Business Health Options Programs, or SHOP exchanges, may find higher costs once they are lumped in with a general-population risk pool.

So we ran the numbers for four companies--of different sizes, in different industries, and in different parts of the country--to see how they plan to deal with all the changes. We've also put together a decision tree to help you learn which mandates, penalties, and incentives you might encounter, as well as a glossary of the ACA's key terms and concepts.

Yes, it's a lot to take in. But you really do not have any choice. And remember: The clock is ticking.