Yes you file it all on the same tax return. The tax for both is included in the total refund or tax due. You file Schedule C in your personal 1040 return for the self employment income.
You pay Self Employment tax (Scheduled SE) on a Net Profit of $400 or more on Schedule C. 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 SE tax will be included in your tax due or reduce your refund. It is on the 1040 Schedule 2 line 4 which goes to 1040 line 23. The SE tax is in addition to your regular income tax on the net profit. You do get to take off the 50% ER portion of the SE tax as an adjustment on 1040 Schedule 1 line 15 which flows to 1040 line 10.
The SE tax includes what you already paid in from your W2s so your schedule SE tax will only be the difference up to the max amount of $9,114.00 for social security. The max income for social security for 2022 is $147,000 between W2 wages and the schedule C Net Profit.
For 2022 the max for Social Security is $9,114.00 on $147,000 of wages (147,000 x 6.2%).
Medicare is 2.9% (both er & ee parts) of all wages & 92.35% Schedule C Net Profit - no max.
You are paying 15.3% for……
SS for employer 6.2% (up to 137,700 wages & profit)
SS for employee 6.2% (up to 137,700 wages & profit)
Medicare for employer 1.45% (on all wages & profit, no max)
Medicare for employee 1.45% (on all wages & profit, no max)
