The dependent care credit (day care expenses if you work full time) is between 20%-35% of expenses up to $3000 for one child or $6000 for two or more children. For most people it will be 20%, but the percentage is higher if your income is lower.
The child tax credit is up to $2000, but can't be more than the tax you owe from your taxable income.
The additional child credit can add some child tax credit if you don't receive the full $2000, but only if you have income earned from working. Even though it's part of the same overall credit, it's calculated differently.
