You send in quarterly estimated payments to cover the income tax and self employment tax (FICA). The Self Employment tax (Scheduled SE) is automatically generated if a person has $400 or more of net profit from self-employment. You pay 15.3% SE tax on 92.35% of your Net Profit (If it is greater than $400). The 15.3% self employed SE Tax is to pay both the employer part and employee part of Social Security and Medicare. So you get social security credit for it when you retire.
The 1040ES quarterly estimates are due April 15, June 16, Sept 15 and Jan 15, 2026. Your state will also have their own estimate forms.
