Yes you can increase your W2 withholding to cover the self employment tax. Yes you still get the 50% SE tax deduction on the Net Profit.
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. If you also have W2 income, you have to break out the Social Security and Medicare taxes. Only the Social Security part maxes out.
For 2022 the max for Social Security is $9,114.00 on $147,000 of wages (147,000 x 6.2%).
For 2023 the max for Social Security is $9,932.40 on $160,200 of wages (160,200 x 6.2%).
