Can I enter a value for my contributions in Block 5 of 1099-R if its left blank

[banksfam]

I took a distribution from the annuity and my contributions were post tax and I just want to pay taxes on the taxable amount

[ColeenD3]

It is a better idea to get a corrected 1099-R. The information you provide must match the form. The IRS will scrutinize your return looking for discrepancies.

[dmertz]

Was the entire annuity surrendered?

Is box 2b Taxable amount not determined marked on the Form 1099-R?

Is a taxable amount shown in box 2a that is different from the amount in box 1?