Here are the 2014 IRS Tax Tables:
https://www.irs.gov/pub/irs-prior/i1040tt--2014.pdf
TurboTax doesn't always calculate your tax due directly from the Tax Tables. If you have capital gains or qualified dividends, for instance, then the calculation is done on the Qualified Dividends and Capital Gains Tax Worksheet, since those income items are taxed more favorably than ordinary income. If you have those types of income, see this FAQ:
https://ttlc.intuit.com/replies/3300459
