In a non-retirement account, Do I have to pay tax for money made in a stock if I havn't sold the stock yet?

In order to accuarately calculate exactly how much I've made in a stock don't I need to wait until I sell it first? What if I've held it for years? Do I have to pay taxes very year on the same stock even if I've held on to it?

You only report the sale of stocks on schedule D (Form 1040). If you hold a stock for more than a year, you have long term capital gain or loss. If you sell a stock within one year of purchase, you have short term capital gain or loss.

If you did not sell a stock, you don't have income or loss on that stock.

Only when you sell.

The only time you report phantom gains is if you exercised an incentive stock option.

You don't have to worry about whether you owe on stocks.
You will receive a 1099 form telling you how much you have earned. The IRS will be informed automatically, computers you know. Capital gains, interest, dividends will all be neatly arranged so you can figure your taxes.

you pay only when you sell and only if you made a profit.

dont be the guy who sells his car and reports that as income because he thinks thats income. For most everyone its not i would say 90% dont need to report it as income.