Deducting Computer from Income Taxes

[Officer Farva]

Hi. I'm sure this topic has been covered at length or this or an other forum. I apologize if this is the wrong place to post, but:

I am about to purchase a computer for my home. I will be claiming it as an un-reimbursed business expense. As such, I need to document the fraction of time it is actually used for business. I anticipate that I will use it 25% for my day job, 60% for poker, and the rest for personal use. Given that I show a profit YTD from poker, can I claim 85% of the cost as deductable? Is poker a valid "business" that I can attach to given that it is a source of income? If my poker income is less that 60% of the computer cost (giving me negative income from the poker business) can I still deduct the entire 85% from my cumulative income?

Thanks in advance for any help.