Not tax advice. A rough estimate only. This follows the main lines of the 2026 Form 1040-ES worksheet with simple inputs. It leaves out things like the additional 0.9% Medicare tax, capital gains rates, AMT and most credits. Use the IRS worksheet or a tax professional for your actual payments.
If nobody withholds tax from your freelance or side income, the IRS expects you to pay during the year through quarterly estimated tax payments. All figures below are from the 2026 Form 1040-ES and the IRS self-employment tax page (checked Oct 31, 2026).
Generally yes, if you expect to owe at least $1,000 for 2026 after withholding and refundable credits, and your withholding and credits will be less than the smaller of 90% of your 2026 tax or 100% of your 2025 tax. Use 110% instead of 100% if your 2025 AGI was over $150,000 ($75,000 if married filing separately).
The rate is 15.3%: 12.4% Social Security plus 2.9% Medicare. It applies to 92.35% of your net profit. For 2026, the Social Security part stops once your wages plus net earnings reach $184,500. Half of the SE tax is deducted when figuring AGI. If net earnings are under $400, no SE tax is due.
Example: $60,000 profit × 92.35% = $55,410 × 15.3% = $8,477.73 SE tax, so the deduction is $4,238.87.
Start with expected AGI: profit, plus other income, minus half the SE tax. Subtract your deduction. The 2026 standard deduction is $16,100 for single or married filing separately, $24,150 for head of household, and $32,200 for married filing jointly or qualifying surviving spouse. Then apply the 2026 rate schedule. For single filers: 10% to $12,400; 12% to $50,400; 22% to $105,700; 24% to $201,775; 32% to $256,225; 35% to $640,600; 37% above that.
Continuing the single example: AGI $55,761.13 − $16,100 = $39,661.13 taxable. Tax = $1,240 + 12% × ($39,661.13 − $12,400) = $4,511.34.
Total ≈ $4,511.34 + $8,477.73 = $12,989.07. 90% is $11,690.16, so with no withholding and no prior-year figure the rough payment is $2,922.54 per quarter. If your 2025 tax was $5,000 (and AGI was under $150,000), the safe harbor is the smaller amount, $5,000, or $1,250 per quarter.
With profit in B1, SE tax in B2:
=ROUND(B1*0.9235*0.029+MIN(B1*0.9235,184500)*0.124,2)
Single-filer income tax on taxable income in B5 (2026 Schedule X):
=ROUND(SUMPRODUCT((B5>{0,12400,50400,105700,201775,256225,640600})*(B5-{0,12400,50400,105700,201775,256225,640600})*{0.10,0.02,0.10,0.02,0.08,0.03,0.02}),2)The second array holds the rate increases between brackets. Both formulas assume no wages; with wages, reduce 184500 by your Social Security wages.
Generally yes, if you expect to owe at least $1,000 for 2026 after withholding and refundable credits, and withholding will be less than the smaller of 90% of your 2026 tax or 100% of your 2025 tax (110% if 2025 AGI was over $150,000).
15.3% (12.4% Social Security plus 2.9% Medicare) on 92.35% of net profit. For 2026 the Social Security part stops at $184,500 of combined wages and net earnings.
April 15, 2026; June 15, 2026; Sept. 15, 2026; and Jan. 15, 2027. You can skip the January payment if you file by Feb. 1, 2027 and pay in full.
Skip the formulas: the free Quarterly Estimated Tax Calculator does this in your browser. Nothing is uploaded.
Just starting out? Grab the free Starter Expense Tracker (pay what you want, $0 is fine).