After the standard deduction, that'd still put them in the 12% bracket, even if they're single. And that 12% is just the marginal rate, not the overall rate.

If single person made $60k in 2025, and only got the standard personal deduction ($15,750), that deduction drops their taxable income to $44,250. Of that:
The first $11,925 is taxed at 10%, so $1,192.
The rest ($32,325 = $44,250-$11,925) is taxed at 12%, so $3,879.
Their total income tax is thus $5,071 (=$1,192+$3,879).
$5,071 / $60,000 = 0.08452, meaning they'd pay an effective tax rate of 8.452%.