In you made no after-tax contributions to the plan, the entire amount is taxable. Otherwise, the Simplified Method must be used to calculate the taxable amount. When entering the CSA 1099-R and TurboTax asks about the taxable amount, indicate that you got regular payments from this retirement account, then TurboTax will ask addition questions the answers to which will cause TurboTax to treat the entire distribution as taxable or will present you with the option to use the Simplified Method. When using the Simplified Method, the Plan Cost is the amount of the after-tax contributions you made to the plan.
