This, from the 4952 instructions:
Gross income from property held for investment includes income, unless derived in the ordinary course of a trade or business, from interest, ordinary dividends (except Alaska Permanent Fund dividends), annuities, and royalties. Include investment income reported to you on Schedule K-1 from a partnership or an S corporation. Also include net investment income from an estate or a trust. Also include on line 4a (or 4d, if applicable) net passive income from a passive activity of a publicly traded partnership (as defined in section 469(k)(2)). See Regulations sections 1.469-10 and 1.7704-1 (including the transition rule of section 1.7704-1(l)), for details. Net income from certain passive activities, such as rental of substantially nondepreciable property, may have to be recharacterized and included on line 4a.
Turbo Tax figures it for you automatically, but if you want a manual calculation, it's
line 8 of your 1040 + line 9 of your 1040 + annuity income (reported on 16b) + royalties (reported on line 17).
1. Go to My Account.
2. Go to Tools.
3. Go to View Tax Summary.
4. Go to Preview my 1040.