Beginner investing

If I invest $10,000 in an individual taxable brokerage account for growth at moderate risk between stocks and bonds. And left for lets say 5 years (hypothetically speaking), it grows to lets say $15,000 within that timeframe. If i then attempt to make a 100% withdrawal (saying broker fees=0.25%) how much tax you think would be taking from that amount or what tax bracket would it be in? The tax part is where I get lost. Thanks!