Withdrawing IRA Basis. When you withdraw money from your traditional IRA as a distribution or by rolling it over into a Roth IRA, you can’t take out only your IRA basis. Instead, the percentage of your IRA balance that is your basis determines the percentage of the withdrawal that counts as basis dollars.RA Basis. You only have an IRA basis when you make nondeductible contributions to a traditional IRA. You can usually deduct your IRA contributions up to the $5,000 annual limit, or $6,000 when you turn 50.