Click here to watch "Try This."

After several weeks of back-and-forth between John McCain and Barack Obama over their respective philosophies on taxes, the Illinois senator is encouraging voters to find out for themselves which candidate's tax plan would benefit them more.

In a new TV ad, "Try This" (subscription), Obama directs viewers to TaxCutFacts.org, where they can plug in their income, marital status and number of dependents and calculate how much they would save with each candidate. "The independent Tax Policy Center says Obama offers middle-class tax cuts three times as big as McCain’s," the announcer says, adding that "1.5 million have tried it. You should too."