You would have to enter each of your income, each of your itemized deductions, and each of your withholdings to figure that out. This is a public forum, nobody sees your return.
Ex say you made $100k, your spouse make $150k
You had taxes withheld of $30k, she had $50k.
You can assume itemized or std. deduction is 50/50 or adjust.
take spouse 1 income adjusted for their portions of deductions/ TOTAL AGI to figure their percentage of the taxes owed, and do that for the spouse. that is each spouses liability.
Then take what was withheld spouse 1 less spouse 1 liability to figure their refund, do the same for spouse 2
There is no individual refund amount on a joint tax return. Everything is combined and there is only one refund calculation. The refund belongs to both of you jointly. The calculation of the refund is based on your total combined income, the amount of tax that the two of you together have to pay on that combined income, and the total combined amount of tax that you paid through withholding or estimated tax payments. It is not calculated separately for each person.
Why are you trying to figure out individual refund amounts? If you are trying to divide the refund between you, you can split it in any way that seems fair to the two of you.
There may be no precise way if you had items like long-term capital gains, qualified dividends, REIT dividends that qualify for the 199A deduction. and certain other items that can skew the taxes so they're not in proportion to either adjusted gross income or taxable income.