Grain of salt disclaimer:(Consult a professional, lawyer, accountant, doctor as I’m a computer engineer, musician, and painter I’m clearly none of those.)
Also read this https://www.irs.gov/instructions/i8949 if you need to fill out 8949.
I hope this is a clear explanation of how capital gains taxes work in general.
Here’s an example of what I would do normally assuming a FIFO tax treatment:
You need to pay tax on your capital gains but you want to subtract your cost basis from the total value you sold for as the basis is not taxed as a gain. (Note that if you can’t prove the cost basis I believe the entire sale of 0.49 at 400 would be considered taxable)
{sold value – cost basis = capital gain} that you need to pay tax on (income tax if under 12 months, 15% if it’s a long term gain)
First find the cost basis.
(0.2*100)+(0.3*120)=20+36=$56 (this is your cost basis)
(I’m going to round your 0.49 eth up to 0.50 as a clear example with round numbers)
Then compute the amount generated from the sale (I’m calling this a sold value)
0.5*400= $200 (this is your sold value in my example equation)
Now find the capital gain using the equation below:
sold value – cost basis = capital gain
200-56=$144
For long term gains over 12 months it’s 15% * your gain minus the cost basis
144*0.15=$21.50 due in taxes.
For short term gain (held under 12 months, as is your case) the gain is considered income.
144*your tax rate = what you owe to the IRS as this was a capital gain. This gets added to your AGI so if you have an AGI of 200,000 your AGI is now 200,144 and the 144 gets taxed as ordinary income.
Regards
