Simple answer: 25%. In addition to income tax, you will have to pay "Self employment tax" (SET-social security and medicare).
The actual amount depends on other factors. You can use this tool to do an estimate <a rel="nofollow" target="_blank" href="
https://turbotax.intuit.com/tax-tools/calculators/taxcaster/?s=1">https://turbotax.intuit.com/tax-to...>
