There is a dollar limit on the amount of your work-related expenses you can use to figure the credit. This limit is $3,000 for one qualifying person, or $6,000 for two or more qualifying persons.So if there are two or more dependents, it's a maximum of $6,000 still. (IRS Pub 503 page 12 at https://www.irs.gov/pub/irs-pdf/p503.pdf)
Additionally, If you received dependent care benefits that you exclude or deduct from your income, you must subtract that amount from the dollar limit that applies to you. With only one dependent if you received more than $3000 tax free for dependent care, then you don't qualify for any child care credit.
If you have two or more dependents that you paid childcare for and received $5000 tax free from your employer, then you only qualify for $1000 of the credit.
