Depending on an individual or his family's income, he may be required to pay various percentages of that income in federal income taxes. Common sources of income are regular employment wages, profits on sales of property and various other sources; however, most individuals wondering whether they have to file a tax return are concerned mostly with their income from wages.

Single Individuals

For single individuals, the maximum amount of money that can be earned before taxes must be paid is $9,349. This applies to those under age 65 who cannot be claimed as a dependent by someone else. For those age 65 and older, this figure increases to $10,749, again, if they are not claimed as a dependent by another.

Married Individuals

For married individuals filing jointly who are both under age 65, the maximum household income that can be earned before having to file is $18,699. If only one spouse is younger than 65, that figure increases to $19,799. If both spouses are 65 or older, the maximum tax-exempt level of household income is $20,899. If a married couple files separately, each must have less than $3,650 in individual income to be tax exempt.

Head of Household

If an individual is filing income taxes as the head of a household and he is under 65, he must make less than $12,000 to be tax exempt. If he is 65 or older, that figure increases to $13,400.

Qualifying Widower

The upper limit for being tax-exempt as a qualifying widower is $15,049 if under age 65 and $16,149 if 65 or older.