How do I calculate my stock cost basis?

Your sale on 2/27 gets reported as a short term gain on Schedule D. Your proceeds are $2900 and your cost is $2600. Purchase date is 2/10. When you purchase 2000 shares on 3/5, you would own 2000 shares with a purchase date of 2/10 @ 2.60 and 2000 shares with a purchase date of 3/5 @ $2.4. If you sell shares in the future and do not provide any specific written instructions to your broker as to exactly wheich shares are to be sold, tax law requires you use FIFO (first in first out) to determine which shares you sold. You are not allowed to use average cost for the sale of stock. You only use "various" as a date if a transaction to sell includes shares that were purchased on different dates and those shares are all in the same category (short or long term).

calculate stock cost basis.

How do you provide these instructions to your broker? Does ETrade, Ameritrade, etc let you do it?

calculate stock cost basis.

Just ask them what they require in the way of documentation. Remember this: you must receive written confirmation from the broker. Typically, you would call the broker after your online trade is acknowledged; tell them which shares were sold; and request written (e-mail is okay) confirmation.

It is really simple to calculate an adjusted cost basis for securities. Just go to

This looks to be a fee based product. Am I missing something?

Yahoo and perhaps others will give historical prices for free, adjusted for splits and corporate events (not sure how well it handles spin-offs).