1099 Quarterly Estimated Tax Planner
Example: Expected net self-employment income: 80000 $ · Other income (W-2, investments, etc.): 0 $ · Total tax paid last year (from prior Form 1040 line 24): 12000 $ · Estimated tax already paid this year: 0 $ · Filing status (0 = Single, 1 = Married Filing Jointly): 0
| Estimated payment per quarter | $3,000 |
| Self-employment tax (Social Security + Medicare) | $11,304 |
| Total estimated tax (income + SE tax) | $18,830 |
| Safe harbor total (min to avoid penalty) | $12,000 |
| Remaining due in quarterly payments | $12,000 |
| Underpayment risk flag (1 = at risk, 0 = safe) | 1 |
Worked example
A single freelancer with $80,000 net self-employment income owes about $11,304 in SE tax (15.3% on 92.35% of $80,000). After the deductible half of that SE tax ($5,652) and the 2026 standard deduction ($16,100), taxable income is $58,248, generating about $7,527 in income tax. Total: ~$18,830. Last year's tax was $12,000, making the safe harbor $12,000. Divided over 4 quarters: $3,000 per quarter minimum, or $4,708 to pay the full estimate and avoid any April surprise.
Frequently asked questions
When are quarterly payments due for 2026?
The statutory instalment dates are April 15, June 15 and September 15 of the tax year and January 15 of the next, shifting to the following business day whenever one falls on a weekend or a holiday. For 2026 none of them do, so the dates are April 15, June 15, September 15, 2026 and January 15, 2027. Missing a payment does not trigger an immediate penalty — the IRS calculates a penalty at filing based on underpayment in each period. Paying on time, even in unequal amounts, avoids interest.
What is the safe harbor rule for estimated taxes?
You avoid the underpayment penalty if you pay at least 90% of this year's tax OR 100% of last year's total tax (110% if last year's AGI exceeded $150,000). Paying the prior-year safe harbor amount is often the safer strategy because you do not need to estimate this year's income precisely.
Can I pay all four quarters at once?
You can overpay early quarters without penalty. Many self-employed people pay a lump sum by January 15 to cover the prior year's Q4. However, spreading payments more evenly through the year improves cash flow and reduces the risk of a large April bill.