Key numbers to know when filing your 2012 tax returns, according to the Internal Revenue Service:

PERSONAL EXEMPTION:

—Each personal or dependent exemption is worth $3,800.

STANDARD DEDUCTION:

—$11,900 for married couples filing a joint return, and qualifying widows and widowers

—$5,950 for singles and married individuals filing separate returns

—$8,700 for heads of household

—Taxpayers who are 65 or older or who are blind may be eligible for a higher standard deduction.

ALTERNATIVE MINIMUM TAX THRESHOLD:

—$78,750 for a married couple filing a joint return, and qualifying widows and widowers

—$50,600 for singles and heads of household

INCOME TAX BRACKETS:

—10 percent, 15 percent, 25 percent, 28 percent, 33 percent, 35 percent

EARNED INCOME TAX CREDIT:

To qualify income can be no greater than:

—$45,060 ($50,270 married filing jointly) with three or more qualifying children

—$41,952 ($47,162 married filing jointly) with two qualifying children

—$36,920 ($42,130 married filing jointly) with one qualifying child

—$13,980 ($19,190 married filing jointly) with no qualifying children

Investment income cannot be more than $3,200 or less for the year.

Maximum credit:

—$5,891 with three or more qualifying children

—$5,236 with two qualifying children

—$3,169 with one qualifying child

—$475 with no qualifying children

CAPITAL GAINS:

—0 percent if taxpayer is in the 10 percent or 15 percent income tax brackets

—15 percent top rate if taxed in higher brackets

ESTATE TAX

—Taxed at a top rate of 35 percent in 2012, with the first $5.12 million in value exempted for individual estates and $10.24 million for family estates

IRA CONTRIBUTIONS:

—Traditional IRA contribution limit: $5,000

—Additional contribution if over 50: $1,000

DEFERRED RETIREMENT ACCOUNTS

— 401(k), 403(b),: $17,000

—Additional contribution if 50 or older: $5,500

STANDARD MILEAGE RATES:

Business use

—55.5 cents a mile

Medical reasons or qualified move

—23 cents a mile

Charitable purposes

—14 cents a mile