Ohio does a convoluted tax calculation for non-residents/part year residents. It calculates tax on total income, then it calculates a non resident/part year resident credit, which it subtracts from the tax it calculated on the total income.
Because tax is calculated on all your income (and your spouse's on a joint return), you are allowed the Joint Filing Credit (JFC) on all your income, not just your OH income. In the "forms mode", look at the Joint Filing Credit Allocation Worksheet. This is where your net qualifying income is calculated. It shows on line 4.
The non resident credit is calculated as your non-Ohio income divided by Total adjusted Income multiplied by the total tax. TurboTax (TT) does this by allocating your income as either Ohio or non-Ohio. W-2 income will be allocated by the state name abbreviation shown in box 15 of your W-2. TT will ask you, item by item, in the state section, how much of your other income is Ohio or non-Ohio income. Make sure that your non-Ohio wages (if any) show NY in box 15 of your W-2 screen, with the NY amount in box 16.
