Traditional IRA total basis

[yatoshura]

When reporting my traditional IRA contribution, TurboTax asked for my total basis.I have multiple IRA accounts for 10 years and I did not consistently contribute every year. I don't remember exactly what the total amount I contributed for past 19 years and I don't remember all the brokers that I have used. Can I simply put a rough estimate for this total amount? What does it impact?

[MaryK4]

You need to keep track of all nondeductible traditional IRA contributions so that you are taxed the correct amount.  It is especially important because if your IRA contains both pre-tax and after-tax money, you cannot choose to withdraw only the tax-free part. The IRS uses a formula to make every withdrawal a proportional mix of both. 

[yatoshura]

What is the best way to find out the total amount as of 2025? Would any of my old tax returns have the amount? Or do I need to check with IRS? Please advise if there is good way to determine this amount since I have not been tracking.

[MaryK4]

The best way to determine your total traditional IRA basis for 2025 is to check your most recently filed Form 8606, specifically Line 14. This form is cumulative and carries your lifetime after-tax (nondeductible) contribution total forward from year to year. 

If you used TurboTax, it will be one of the forms in your return.  You can also get the information from the IRS- the Wage and Income transcript shows Form 5498 data for the past 10 years, which lists all IRA contributions reported by your brokers.  You can also request this to see if a Form 8606 was ever filed with your past returns (you will have to call).  
 

Use the IRS Get Transcript tool online, which is the fastest method, or call the automated line at 800-908-9946.

@yatoshura

[Mike9241]

you have no basis for any contributions you deducted. If you made any that you didn't deduct, then Form 8606 should have been generated.