your federal refund is never taxable, state refund may be taxable if you took a deduction for state income taxes rather than state sales taxes. if you used Turbotax in 2023 and took a state income tax deduction, it should be able to compute the taxable portion of the refund automatically.
to check the computation you can use worksheets 2a and 2 in IS PUB 525. Turbotax also has similar worksheets but you can't see them until you pay any Turbotax fees.
https://www.irs.gov/pub/irs-pdf/p525.pdf
