$100k income generates $20981.75 federal income tax. FICA is paid on the full amount, so $15300. In my state, the top income tax rate is 4.9%, but with graduation, $4620.50. All together, that's $40902.25, or about 41%. That's not that far off the 45% estimate from above, but it is lower. I still contend that taxes on small businesses are still absurdly high.
If you're going to run numbers you might as well use a calculator that at least accounts for the standard deduction, personal exemption, and deducts 1/2 of the SE tax:
Income: $100,000
Self-employment tax on $100,000: $14,130
Taxable income: $100,000 - $6,300 (standard deduction) - $4,050 (personal exemption) - $7,065 (1/2 SE tax) = $82,585
Federal income tax on $82,585 = $16,418
Total federal income tax and self-employment tax: $30,548
That's about 30%. Add in $4-5k for state income tax and you're up to 35% effective tax rate at most. And this is assuming a single filer with no dependents and no other deductions. Add a spouse or dependents, or IRA/401k contributions, or business deductions, and it goes even lower.
Let me see if I can push out better numbers. From here:
http://taxfoundation.org/article/2017-tax-brackets
https://www.tax-brackets.org/newmexicotaxtable
$100k income generates $20981.75 federal income tax. FICA is paid on the full amount, so $15300. In my state, the top income tax rate is 4.9%, but with graduation, $4620.50. All together, that's $40902.25, or about 41%. That's not that far off the 45% estimate from above, but it is lower. I still contend that taxes on small businesses are still absurdly high.