Final answer:
A married couple may exclude up to $500,000 of gain from the sale of their principal residence from gross income, provided they meet the IRS criteria.
Step-by-step explanation:
The maxmum amount of gain on the sale of a principal residence that a married couple may exclude from gross income is $500,000. This exclusion is available when filing a joint tax return and provided that certain IRS requirements are met, such as owning and using thie home as a principal residence for at least two of the five years before the sale. It is important to note that this exclusion can not be claimed if it has been claimed on another property within the last two years.