Taxpayers who pay for child care or dependent care, enabling them to be gainfully employed, are allowed a credit against income tax for a portion of such expenses.

However, a married person with a nonworking spouse usually cannot claim the credit unless the nonworking spouse is physically or mentally disabled or is a full-time student for at least five calendar months during the year.

The tax credit applies to costs incurred in any of three categories:

Any dependent under the age of 13 for whom the taxpayer is entitled to claim a dependency exemption.

Any dependent, regardless of age, who is physically or mentally incapable of self help.

A disabled spouse.

In order for the dependent-care expenses to be considered as "employment related" and, thus, qualifying for the tax credit, they must be qualified expenses for household services or child-care services outside the household.

In general, the household services must be ordinary and usual services performed in and about the home that are necessary for the operation of the home and the well-being of one or more qualifying dependents.

The services of a housekeeper, maid, or cook ordinarily are considered necessary to the operation of the household if performed at least partially for the benefit of such dependent.

However, amounts paid for the services of an individual employed as a chauffeur, bartender, or gardener are not considered to be expenses paid for household services.

Expenses incurred in connection with employing the person who actually provides the child- or dependent-care services, including expenditures that are personal as well as business in nature, usually qualify.

The portion of expenditures allocable to an employed nursemaid for meals and lodging may be employment related, as is the taxpayer's share of the employee's Social Security tax.

For example: A divorced taxpayer with a 4-year-old child in her household is forced to move to a larger apartment because a housekeeper had to be employed on a full-time basis.

The additional rent required for this extra bedroom, as well as additional utility expenses incurred, may be taken into account.

Occasionally, the person employed to provide child- and dependent-care service, during the course of providing that care, also may render some incidental benefit to non-qualifying members of the household or perform some non-household services.

If the services are performed at least partially for the benefit of a qualifying individual, the incidental benefits received by a non-qualifying individual are irrelevant and the expense need not be apportioned.

However, when the individual performing the child- or dependent-care service has significant other, non-related duties, expenses must be apportioned between the household and the non-household expenses to exclude the payments made for non-household services.

Thus, if a cook doubles as a gardener in the taxpayer's household, the expense for the gardening time should be excluded.

Employment-related expenses incurred for services provided outside a taxpayer's household by a dependent-care center may be taken into account for purposes of the credit, as long as the center complies with all applicable state and local laws and regulations.

A dependent-care center is any facility that provides care for more than six individuals and receives a fee, payment or grant for providing services for any of the individuals, regardless of whether the center is operated for profit.

On the other hand, qualifying outside-the-household care expenses do not extend to expenses for a child's education.

Normally, outside-the-household care expenses include the costs of a nursery school or day care for preschool children.

In such case, incidental educational benefits that are an inseparable part of the care need not be apportioned.

However, if the expenses go toward education in the first or higher grade level, they must be apportioned between the cost of care for the child and the cost of education.

Transportation expenses incurred while taking a child to an outside-the-home care location are not child-care expenses.

This confines qualifying expenses to those actually incurred for the care of the child and excludes the indirect expenses that are incurred to enable a child to receive that care.

Employment-related expenses can be used for credit only in the year in which the taxpayer pays them.

For example, if a taxpayer incurs employment-related, dependent-care expenses in December 1990 and pays them in January 1991, these expenses may not be included on the 1990 tax return. Instead, they should be claimed on the tax return for the following year.