You can add W-2 income that either you or your spouse earns to help Hurdlr project the correct tax bracket for your income level, giving you a more accurate tax calculation. However, Hurdlr's Tax Engine doesn't estimate any taxes owed on your W-2 income, since those are already withheld.
To add your annual W-2 salary for yourself or your spouse (assuming you're married filing jointly):
On the mobile app go to the Taxes tab and tap the gear icon in the top right corner or on the web app click the gear icon in the top right corner and select Tax Profile
In Annual W-2 Income setting, enter the total amount of pre-tax W-2 earnings for the entire year