Calculating cost basis for crypto sale if position not closed

[ws4]

Hi and sorry for the noob question. I bought some LTC on Coinbase in 2018 and sold some LTC (but a lower amount than I bought) in 2019. Turbotax didn't accept my CSV file from Coinbase, so I have to enter my taxable transactions myself. (for reference, the information I need to enter is Service, Asset name, Date of purchase, Cost basis, Date of sale, and Proceeds)

I can figure out that if I had closed the position, the cost basis would just be the USD Total (inclusive of fees). However, since I didn't sell all the LTC I hold, can I lower the cost basis by multiplying it by the quantity sold and dividing by the quantity bought?

thx

[MinhT1 · Accepted solution]

Yes, you are correct. If you only sold part of a position, the cost basis is only the cost basis of the items sold, not of the total position.