You can only deduct charitable contributions if you are claiming itemized deductions (Form 1040 Schedule A). If you haven’t seen a difference on your return after entering your charitable amounts, you might be using the standard deduction.
The standard deduction is a dollar amount based on your filing status that reduces the amount of income subject to tax. If you’re legally blind or older than 65, additional amounts are added to the standard deduction.
Credit Karma Tax automatically chooses the deduction that is larger, but you’ll be able to override this automation if you itemize your return. If you choose standard deduction rather than itemizing your deductions, you won’t be able to deduct your charitable contributions.