http://www.fairtaxvolunteer.org/smart/faq-main.html#5
Is the 23% FairTax revenue-neutral rate higher or lower when compared to income and Social Security taxes people pay today? Most people are paying that much or more today – much of it is just hidden from view. The income tax bracket most people fall into is 15 percent, and all wage earners pay 7.65 percent in payroll taxes. That’s 23 percent right there, without taking into account the 7.65 percent employer matching! On top of that, you have to add in the business taxes and associated compliance costs passed on to consumers in higher prices.
Effective tax rates vs. stated tax rates
Because the 23-percent FairTax rate of $0.23 on every dollar spent is not imposed on necessities, an individual spending $30,000 pays an effective tax rate of only 15.5 percent, not 23 percent. That same individual will pay 17.3 percent of his or her income to federal taxes under current law. See effective tax rates for a family of four at various spending levels in Figure 2.
And AFFT's discussion of comparative rates regarding a situation of married with no childern FAQ#14:
http://www.fairtaxvolunteer.org/smart/faq-main.html#14
Is it fair for rich people to get the exact same FairTax rebate from the federal government as the poorest person in America? Let’s look at a billionaire under the FairTax – if he spends $10,000,000 dollars he pays a tax of $2,300,000 and gets a rebate of $4,508 (assuming he is married and has no children). His effective tax rate as a percent of spending is 22.95 percent.
Now, let’s look at a middle-income married couple with no children under the FairTax – if they spend $40,000, they pay $4,692 net of their rebate for an effective tax rate of 11.7 percent. The effective tax rate increases as spending increases, but never exceeds 23 percent!
Figure 4: Comparison of effective tax rates
FairTax Income tax
FairTax
Current Tax
Expenditures = income $40,000
$40,000
Net tax $4,692
$5,870
Effective tax rate 11.7%
14.7%
In contrast, if this same couple earns $40,000 in wages today under the current tax system, they pay $2,810 in income taxes and $3,060 in payroll taxes for a total of $5,870 in taxes (14.7 percent). In addition, their employer pays another $3,060 in payroll taxes. Most economists agree that the employer payroll tax is actually borne by employees in the form of lower wages. Looked at this way, this couple is paying $8,930 (22.3 percent) in taxes today, which doesn’t even include the hidden taxes they pay every time they make a purchase.
Finally, let’s look at a low-income couple under the FairTax – they pay no net FairTax at all. Today, under the income tax system, they not only pay 15 percent in payroll taxes, but they also pay hidden taxes – arising from corporate taxes, private sector compliance costs, and payroll taxes passed on to consumers and embedded in the price of everything they buy.