If you took a lump-sum distribution from a qualified retirement account and were born before January 2, 1936, of if you are the beneficiary of someone who was, you may be able to use different averaging options to figure out how much you owe in taxes.
Go to this section in Credit Karma Tax: Form 1099-R
One method is called the 10-year tax option. If you are eligible to use this method, you may see the letter A in box 7 of your 1099-R. This method allows you to use the 1986 tax rates to calculate the tax on one-tenth of the amount of your distribution and to pay all taxes in the year you take the distribution. The ordinary income part of the lump-sum distribution is treated as a separate tax calculation that does not include any of your other income in the calculation.
If the distribution shows capital gains on box 3 of Form 1099-R, you can also elect to have that portion of income taxed at the capital gain rate of 20% instead of the entire distribution being taxed as ordinary income.
Credit Karma Tax can help you find out if you qualify based on the information you provide.